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1.  Independent Associations of Fasting Insulin, Glucose, and Glycated Haemoglobin with Stroke and Coronary Heart Disease in Older Women 
PLoS Medicine  2007;4(8):e263.
Evidence suggests that variations in fasting glucose and insulin amongst those without frank type 2 diabetes mellitus are important determinants of cardiovascular disease. However, the relative importance of variations in fasting insulin, glucose, and glycated haemoglobin as risk factors for cardiovascular disease in women without diabetes is unclear. Our aim was to determine the independent associations of fasting insulin, glucose, and glycated haemoglobin with coronary heart disease and stroke in older women.
Methods and Findings
We undertook a prospective cohort study of 3,246 British women aged 60–79 y, all of whom were free of baseline coronary heart disease, stroke, and diabetes, and all of whom had fasting glucose levels below 7 mmol/l. Fasting insulin and homeostasis model assessment for insulin sensitivity (HOMA-S) were linearly associated with a combined outcome of coronary heart disease or stroke (n = 219 events), but there was no association of fasting glucose or glycated haemoglobin with these outcomes. Results were similar for coronary heart disease and stroke as separate outcomes. The age, life-course socioeconomic position, smoking, and physical activity adjusted hazard ratio for a combined outcome of incident coronary heart disease or stroke per one standard deviation of fasting insulin was 1.14 (95% CI 1.02–1.33). Additional adjustment for other components of metabolic syndrome, low-density lipoprotein cholesterol, fasting glucose, and glycated haemoglobin had little effect on this result.
Our findings suggest that in women in the 60–79 y age range, insulin resistance, rather than insulin secretion or chronic hyperglycaemia, is a more important risk factor for coronary heart disease and stroke. Below currently used thresholds of fasting glucose for defining diabetes, neither fasting glucose nor glycated haemoglobin are associated with cardiovascular disease.
From a prospective study of women aged 60-79 years, Debbie Lawlor and colleagues conclude that insulin resistance is an important risk factor for coronary heart disease and stroke.
Editors' Summary
Narrowing of the vessels that take blood to the heart and brain is a common form of cardiovascular disease—i.e., a disorder of the heart and blood vessels. It is a major cause of illness and death. By starving the heart and brain of oxygen, this condition causes coronary heart disease (CHD; heart problems such as angina and heart attacks) and strokes. A major risk factor for CHD and strokes is diabetes, a common chronic disease characterized by high levels of sugar (glucose) in the blood. In people who don't have diabetes, the hormone insulin controls blood-sugar levels. Insulin, which is released by the pancreas after eating, “instructs” insulin-responsive muscle and fat cells to absorb the glucose (released from food) from the bloodstream. In the very early stages of type 2 diabetes (the commonest type of diabetes, also called “adult onset” or “noninsulin-dependent” diabetes”), muscle and fat cells become unresponsive to insulin, so blood-sugar levels increase. This is called “insulin resistance.” The pancreas responds by making more insulin. As a result, people with insulin resistance have high blood levels of both insulin (hyperinsulinemia) and glucose (hyperglycemia). Eventually, the insulin-producing cells in the pancreas start to malfunction, insulin secretion decreases, and type 2 diabetes is the result.
Why Was This Study Done?
It is not yet clear whether it is insulin resistance or reduced insulin secretion that is responsible for the association between diabetes and cardiovascular disease. Physicians would like to know this information to help them to prevent CHD and strokes in their patients. There is evidence that variations in fasting glucose levels (blood glucose measured more than 8 h after eating), which provide an indication of how well pancreatic cells are producing insulin, and in fasting insulin levels, which provide an indication of insulin resistance, determine cardiovascular disease risk among people without type 2 diabetes, but the relative importance of these risk factors is unclear. In this study, the researchers have investigated whether markers of insulin resistance (fasting hyperinsulinemia) and of altered insulin secretion (fasting hyperglycemia, and increased glycated hemoglobin, which indicates how much sugar has been in the blood over the past few months) are associated with CHD and strokes in elderly women without diabetes. Their aim is to gain new insights into how diabetes affects cardiovascular disease risk.
What Did the Researchers Do and Find?
The researchers measured glucose, insulin, and glycated hemoglobulin in fasting blood samples taken from about 3,000 women aged 60–79 y when they enrolled in the British Women's Heart and Health Study. None of the women had CHD at enrollment, none had had a stroke, none had diagnosed diabetes, and all had a fasting blood glucose below 7 mmol/l (a higher reading indicates diabetes). After monitoring the women for nearly 5 y for CHD and strokes, the researchers looked for statistical associations between the occurrence of cardiovascular disease and markers of insulin resistance and reduced insulin secretion. They found that fasting insulin levels, but not fasting glucose or glycated hemoglobin levels, were associated with CHD and stroke, even after allowing for other factors that affect cardiovascular disease risk such as smoking and physical activity. In other words, raised fasting insulin levels increased the women's risk of developing cardiovascular disease.
What Do These Findings Mean?
These results indicate that in elderly women without diabetes, fasting insulin (a marker of insulin resistance) is a better predictor of future cardiovascular disease risk than fasting glucose or glycated hemoglobin (markers of reduced insulin secretion). This suggests that insulin resistance might be the main mechanism linking type 2 diabetes to CHD and stroke in elderly women. (Elderly women are known to run a high risk of developing these conditions, but they have been relatively neglected in previous studies of the risk factors for cardiovascular disease.) However, because relatively few women developed CHD during the study and even fewer had a stroke, this conclusion needs confirming in larger studies, preferably ones that include more rigorous tests of insulin resistance and secretion and also include women from more ethnic backgrounds than this study did. If the association between fasting insulin levels and cardiovascular disease risk is confirmed, therapeutic interventions or lifestyle interventions (for example, increased physical activity or weight loss) that prevent or reverse insulin resistance might reduce cardiovascular disease risk better than interventions that prevent chronic hyperglycemia.
Additional Information.
Please access these Web sites via the online version of this summary at
MedlinePlus encyclopedia page on coronary heart disease, stroke, and diabetes (in English and Spanish)
Information for patients and caregivers from the US National Diabetes Information Clearinghouse on diabetes, including information on insulin resistance and on diabetes, heart disease, and stroke
Information on the British Women's Heart and Health Study
PMCID: PMC1952205  PMID: 17760500
2.  Helicobacter pylori infection is identified as a cardiovascular risk factor in Central Africans 
Helicobacter pylori is now incriminated in the pathogenesis of atherosclerosis.
To examine the importance of H. pylori infection as a cardiovascular disease (CVD) risk factor.
Two hundred five patients (128 with H. pylori infection [HP-seropositive] and 77 without) had a baseline assessment for other potential CVD risk factors and were followed prospectively for 10 years (1999–2008). They were assessed on a monthly basis for the outcomes of carotid plaque, angina pectoris, myocardial infarction, and stroke. In the HP-seropositive group, male sex and quartile 4 for IgG anti-H. pylori antibodies (anti-HP Ab) were correlated with traditional CVD risk factors, stroke, myocardial infarction, and angina pectoris.
At the baseline assessment, the levels of carotid intima-media thickness, blood fibrinogen, total cholesterol, fasting plasma glucose, and uric acid were higher in H. pylori-infected patients than in the uninfected group. Serum HDL-cholesterol was significantly lower in the HP-seropositive group. Men had higher levels of IgG anti-HP Ab, waist circumference, blood pressure, uric acid, and total cholesterol than women. Within the HP-seropositive group, individuals in quartile 4 for IgG anti-HP Ab had higher rates of elevated fibrinogen, diabetes mellitus, low high-density lipoprotein cholesterol, arterial hypertension, and high total cholesterol than those in quartile 1. After adjusting for traditional CVD risk factors, H. pylori infection was the only independent predictor of incident carotid plaque (multivariate odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.2–7.2; P < 0.0001) and incident acute stroke (multivariate OR = 3.6, 95% CI: 1.4–8.2; P < 0.0001). Within the HP-seropositive group and after adjusting for traditional CVD risk factors, male sex was the only independent predictor of incident angina pectoris (multivariate OR = 3.5, 95% CI: 1.6–16; P < 0.0001), incident acute stroke (multivariate OR = 3.2, 95% CI: 1.4–28; P < 0.0001), and acute myocardial infarction (multivariate OR = 7.2, 95% CI: 3.1–18; P < 0.0001).
Our study provides evidence for an association among known CVD risk factors, carotid plaque, stroke, and H. pylori infection. Among infected individuals, there is a significant association among severity of HP-seropositivity, male sex, and CVD. The eradication of H. pylori infection may therefore reduce the emerging burden of CVD in Africa.
PMCID: PMC3423148  PMID: 22923995
Helicobacter pylori; stroke; myocardial infarction; cardiovascular disease; carotid plaque; Africans
3.  Prevalence of diabetes and other cardiovascular risk factors in an Iranian population with acute coronary syndrome 
Coronary artery disease is the leading cause of death in industrialized countries and most patients with diabetes die from complications of atherosclerosis. The objective of this study was to determine the presence of diabetes mellitus and other conventional coronary heart disease risk factors (cigarette smoking, hypertension and hyperlipidemia) in patients with acute coronary events in an Iranian population.
The study included 514 patients with unstable angina or myocardial infarction (MI) out of 720 patients admitted to CCU ward of a general hospital from March 2003 to March 2005. History of diabetes, hypertension and cigarette smoking, demographic indices, coronary heart disease and diabetes mellitus treatment, myocardial enzymes, serum triglycerides (TG) and cholesterol and fasting and non fasting blood glucose levels and HbA1C of diabetics were recorded of admission sheets. The data were structured to appropriate one way ANOVA, T tests, and chi square test with SPSS 13 product for windows.
Out of all patients 35.8% were female, 30% were diabetics (Duration 13.4 ± 8.7 years), 42% were smoker and 91% were hypertensive. Twenty four percent had MI and 76% had unstable angina. MI was significantly higher in diabetic patients (36.4% vs. 19.2%, P < 0.001). Location and extension of MI and myocardial enzymes did not differ between diabetics and non-diabetic patients. Diabetic patients were older than non diabetics (65 ± 11.6 vs. 59.7 ± 12.5 years, p < 0.05). Five (66.7%) out of 9 patients with fatal MI were diabetics (Odds Ratio = 2.98). Age, duration of diabetes and HbA1c levels, did not differ between diabetic patients with or without MI. Hypertension and current smoking was significantly higher in patients with MI compared to patients with unstable angina (p < 0.05). Serum TG, HDL-C, LDL-C and total cholesterol level did not differ between patients with MI and unstable angina. Diabetic patients compare to non diabetic patients were more hypertensive (96% vs. 88.7%, p < 0.005) and had higher serum triglyceride (TG over 200 mg/dl, 35.1% vs. 26.4, p <0.05). Diabetes was more frequent among women than men (36.4% vs. 26.4%, p < 0.05). Women were older than men (65 ± 11.6 vs. 59.2 ± 13 years, p < 0.005) and had higher total serum cholesterol (200 ± 41.8 vs. 192 ± 42.5 mg/dl, p < 0.05) and HDL-C levels (49.7 ± 22 vs. 40 ± 13 mg/dl, p < 0.005). Ninety seven percent of all patients had at least one of cardiovascular risk factors (hypertension, smoking, diabetes, high cholesterol and low HDL-cholesterol levels).
In this study 19 out of 20 patients with acute coronary event have at least one of conventional cardiac risk factors. Diabetes and hypertension are leading risk factors, which may directly or indirectly interfere and predict more serious complications of coronary heart disease.
PMCID: PMC1550715  PMID: 16842631
4.  Impact of newly diagnosed abnormal glucose regulation on long-term prognosis in low risk patients with ST-elevation myocardial infarction: A follow-up study 
Patients with acute myocardial infarction and newly detected abnormal glucose regulation have been shown to have a less favourable prognosis compared to patients with normal glucose regulation. The importance and timing of oral glucose tolerance testing (OGTT) in patients with acute myocardial infarction without known diabetes is uncertain. The aim of the present study was to evaluate the impact of abnormal glucose regulation classified by an OGTT in-hospital and at three-month follow-up on clinical outcome in patients with acute ST elevation myocardial infarction (STEMI) without known diabetes.
Patients (n = 224, age 58 years) with a primary percutanous coronary intervention (PCI) treated STEMI were followed for clinical events (all-cause mortality, non-fatal myocardial re-infarction, recurrent ischemia causing hospital admission, and stroke). The patients were classified by a standardised 75 g OGTT at two time points, first, at a median time of 16.5 hours after hospital admission, then at three-month follow-up. Based on the OGTT results, the patients were categorised according to the WHO criteria and the term abnormal glucose regulation was defined as the sum of impaired fasting glucose, impaired glucose tolerance and type 2-diabetes.
The number of patients diagnosed with abnormal glucose regulation in-hospital and at three-month was 105 (47%) and 50 (25%), respectively. During the follow up time of (median) 33 (27, 39) months, 58 (25.9%) patients experienced a new clinical event. There were six deaths, 15 non-fatal re-infarction, 33 recurrent ischemia, and four strokes. Kaplan-Meier analysis of survival free of composite end-points showed similar results in patients with abnormal and normal glucose regulation, both when classified in-hospital (p = 0.4) and re-classified three months later (p = 0.3).
Patients with a primary PCI treated STEMI, without previously known diabetes, appear to have an excellent long-term prognosis, independent of the glucometabolic state classified by an OGTT in-hospital or at three-month follow-up.
Trial registration
The trial is registered at, NCT00926133.
PMCID: PMC3173358  PMID: 21801387
5.  Efficacy of long-term anticoagulant treatment in subgroups of patients after myocardial infarction. 
British Heart Journal  1995;74(2):117-121.
OBJECTIVE--To investigate the efficacy of long term oral anticoagulant treatment in subgroups of patients after myocardial infarction. DESIGN--Analysis of the effect of anticoagulant treatment in subgroups of hospital survivors of myocardial infarction based upon age, gender, history of hypertension, previous myocardial infarction, smoking habits, diabetes mellitus, Killip class, anterior location of infarction, thrombolytic therapy, and use of beta blockers. SUBJECTS--Participants of a multicentre, randomised, double blind, placebo controlled trial that assessed the effect of oral anticoagulant treatment on mortality as well as cerebrovascular and cardiovascular morbidity in 3404 hospital survivors of acute myocardial infarction. MAIN OUTCOME MEASURES--The effect of anticoagulant treatment on recurrent myocardial infarction, cerebrovascular events, and vascular events (the composite endpoint of reinfarction, cerebrovascular event, and vascular death). RESULTS--Long term anticoagulant treatment was associated with a reduction in mortality of 10% (95% confidence interval -11% to 27%), recurrent myocardial infarction of 53% (41% to 62%), cerebrovascular events of 40% (10% to 60%) and vascular events of 35% (24% to 45%). Treatment effect with respect to recurrent myocardial infarction was comparable among all subgroups of patients. Although treatment effect appeared to be somewhat smaller in females than in males (-11% v -45%), and in patients with diabetes compared to those without (-14% v -42%) with respect to vascular events, none of these differences reached statistical significance. In multivariate analysis, more advanced age, previous myocardial infarction, diabetes mellitus, and heart failure during admission were independently associated with increased incidence of cardiovascular complications. CONCLUSIONS--The relative benefit of long term anticoagulant therapy in survivors of myocardial infarction is not modified by known prognostic factors for cardiovascular disease.
PMCID: PMC483984  PMID: 7546987
6.  Impact of post-challenge hyperglycemia on clinical outcomes in japanese patients with stable angina undergoing percutaneous coronary intervention 
Post-challenge hyperglycemia (PH) is well-established as one of risk factors for coronary artery disease. However, it remains unclear whether PH affects clinical outcomes in patients with stable angina undergoing percutaneous coronary intervention (PCI).
A total of 828 patients with stable angina undergoing PCI were retrospectively analyzed. Of these, 452 patients with previously diagnosed diabetes mellitus (DM) or fasting plasma glucose (PG) ≥126 mg/dl and HbA1c ≥6.5% were defined as known DM. The remaining 376 patients were divided into the two groups according to 2-h PG: PH (2-h PG ≥140 mg/dl, n=236) and normal glucose tolerance (NGT, 2-h PG <140 mg/dl, n=140). We assessed the rate of major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, myocardial infarction, stroke, and clinically-driven revascularization.
During the median follow-up of 4.3 years, the MACE rate was significantly higher in the DM and PH groups than the NGT group (39.3% vs. 20.7%, P <0.001; 31.4% vs. 20.7%, P=0.044, respectively). Compared with the NGT group, the cumulative incidence of revascularization was significantly higher in the DM group (35.1% vs. 18.5%, P <0.001) and tended to be higher in the PH group (27.1% vs. 18.5%, P=0.067). In the multivariate analysis, known DM (Hazard ratio [HR]: 2.16, 95% confidence interval (CI): 1.49-3.27, P < 0.001), PH (HR: 1.62, 95% CI: 1.07-2.53, P = 0.023), LDL-C >100 mg/dl (HR: 1.62, 95% CI: 1.26 to 2.10, P < 0.001), and previous stroke (HR: 1.47, 95% CI: 1.03-2.04, P = 0.034) were predictors of MACE.
PH is associated with future cardiovascular events in patients with stable angina undergoing PCI.
PMCID: PMC3651729  PMID: 23651930
Coronary artery disease; Diabetes mellitus; Percutaneous coronary intervention; Post-challenge hyperglycemia; Stable angina
7.  Rationale, design, and baseline characteristics of a randomized, placebo-controlled cardiovascular outcome trial of empagliflozin (EMPA-REG OUTCOME™) 
Evidence concerning the importance of glucose lowering in the prevention of cardiovascular (CV) outcomes remains controversial. Given the multi-faceted pathogenesis of atherosclerosis in diabetes, it is likely that any intervention to mitigate this risk must address CV risk factors beyond glycemia alone. The SGLT-2 inhibitor empagliflozin improves glucose control, body weight and blood pressure when used as monotherapy or add-on to other antihyperglycemic agents in patients with type 2 diabetes. The aim of the ongoing EMPA-REG OUTCOME™ trial is to determine the long-term CV safety of empagliflozin, as well as investigating potential benefits on macro-/microvascular outcomes.
Patients who were drug-naïve (HbA1c ≥7.0% and ≤9.0%), or on background glucose-lowering therapy (HbA1c ≥7.0% and ≤10.0%), and were at high risk of CV events, were randomized (1:1:1) and treated with empagliflozin 10 mg, empagliflozin 25 mg, or placebo (double blind, double dummy) superimposed upon the standard of care. The primary outcome is time to first occurrence of CV death, non-fatal myocardial infarction, or non-fatal stroke. CV events will be prospectively adjudicated by an independent Clinical Events Committee. The trial will continue until ≥691 confirmed primary outcome events have occurred, providing a power of 90% to yield an upper limit of the adjusted 95% CI for a hazard ratio of <1.3 with a one-sided α of 0.025, assuming equal risks between placebo and empagliflozin (both doses pooled). Hierarchical testing for superiority will follow for the primary outcome and key secondary outcomes (time to first occurrence of CV death, non-fatal myocardial infarction, non-fatal stroke or hospitalization for unstable angina pectoris) where non-inferiority is achieved.
Between Sept 2010 and April 2013, 592 clinical sites randomized and treated 7034 patients (41% from Europe, 20% from North America, and 19% from Asia). At baseline, the mean age was 63 ± 9 years, BMI 30.6 ± 5.3 kg/m2, HbA1c 8.1 ± 0.8%, and eGFR 74 ± 21 ml/min/1.73 m2. The study is expected to report in 2015.
EMPA-REG OUTCOME™ will determine the CV safety of empagliflozin in a cohort of patients with type 2 diabetes and high CV risk, with the potential to show cardioprotection.
Trial registration NCT01131676
PMCID: PMC4072621  PMID: 24943000
Blood pressure; Body weight; Empagliflozin; Glycemic control; Macrovascular; Microvascular; SGLT2 inhibitor; Type 2 diabetes
8.  Survival of the fattest: unexpected findings about hyperglycaemia and obesity in a population based study of 75-year-olds 
BMJ Open  2011;1(1):e000012.
To study the relationship between body mass index (BMI) and mortality among 75-year-olds with and without diabetes mellitus type 2 (DM) or impaired fasting glucose (IFG).
Prospective population-based cohort study with a 10-year follow-up.
A random sample of 618 of the 1100 inhabitants born in 1922 and living in the city of Västerås in 1997 were invited to participate in a cardiovascular health survey; 70% of those invited agreed to participate (432 individuals: 210 men, 222 women).
Outcome measures
All-cause and cardiovascular mortality.
163 of 432 (38%) participants died during the 10-year follow-up period. The prevalence of DM or IFG was 41% (35% among survivors, 48% among non-survivors). The prevalence of obesity/overweight/normal weight/underweight according to WHO definitions was 12/45/42/1% (14/43/42/1% among survivors, 9/47/42/2% among non-survivors). The hazard rate for death decreased by 10% for every kg/m2 increase in BMI in individuals with DM/IFG (HR 0.91, 95% CI 0.86 to 0.97; p=0.003). After adjustment for sex, current smoking, diagnosed hypertension, diagnosed angina pectoris, previous myocardial infarction and previous stroke/transient ischaemic attack, the corresponding decrease in mortality was 9% (HR 0.92, 95% CI 0.86 to 0.99; p=0.017). These findings remained after exclusion of individuals with BMI<20 or those who died within 2-year follow-up. In individuals without DM/IFG, BMI had no effect on mortality (HR 1.01, 95% CI 0.95 to 1.07; p=0.811). The HR for BMI differed significantly between individuals with and without DM/IFG (p interaction=0.025). The increased all-cause mortality in individuals with DM/IFG in combination with lower BMI was driven by cardiovascular death.
High all-cause and cardiovascular mortality was associated with lower BMI in 75-year-olds with DM/IFG but not in those without DM/IFG. Further studies on the combined effect of obesity/overweight and DM/IFG are needed in order to assess the appropriateness of current guideline recommendations for weight reduction in older people with DM/IFG.
Article summary
Article focus
To explore the combined effect of hyperglycaemia and body mass index (BMI) on all-cause and cardiovascular mortality in the elderly.
Key messages
There was a significant inverse relationship in 75-year-olds with type 2 diabetes mellitus (DM) or impaired fasting glucose (IFG) between BMI and rate of all-cause and cardiovascular mortality.
An obesity paradox or reverse epidemiology was found in 75-year-olds with DM or IFG.
Further studies on the combined effect of obesity/overweight and DM/IFG are needed in order to assess current guidelines for weight reduction in older people with DM/IFG.
Strengths and limitations of this study
Restricting our investigation to one age group enabled us to omit age as a confounding factor, allowing meaningful estimation of the relationship between all-cause and cardiovascular mortality and BMI in individuals with and without hyperglycaemia, despite the relatively small number of study participants. Furthermore, because of the high participation rate, the participants are more representative of the population in a defined geographical area than described in most other studies on this topic. These advantages are, however, offset by difficulty in generalising our findings to those in other age groups and from other geographical areas. Nevertheless, it seems likely that our results are applicable to Northern Europeans and white North Americans in their seventies.
A further limitation of the study is the fact that mortality among invited individuals who did not participate in the study (30%) was considerably higher than among those who participated (70%), mainly reflecting a higher prevalence of diseases under treatment among non-participants.
PMCID: PMC3191391  PMID: 22021724
BMI; cardiovascular diseases; elderly; fasting glucose; mortality; obesity paradox; epidemiology; Computers; meta-analysis; statistics; BMJ open
9.  Association between Low Serum Magnesium Level and Major Adverse Cardiac Events in Patients Treated with Drug-Eluting Stents for Acute Myocardial Infarction 
PLoS ONE  2014;9(6):e98971.
We investigated the association of serum magnesium (Mg) levels and major adverse cardiac events (MACEs) after drug-eluting stent (DES) implantation.
Mg depletion plays a key role in the pathphysiologic features of diabetes mellitus, hypertension, thrombosis, arrhythmias and coronary artery disease. Whether the depletion is related to the long-term prognosis of DES implantation is not known.
From 2008 to 2011, we enrolled 414 consecutive patients <50 years old who underwent DES implantation for acute coronary syndrome. Serum Mg level was analyzed and patients were followed up for a median of 24 months (interquartile range 14–32 months) for the occurrence of MACEs defined as death, myocardial infarction, stroke, and any revascularization.
For patients with unstable angina, no significant association between serum Mg level and MACEs was found in the multivariate model. For patients with myocardial infarction, after adjusting for age, positive family history, smoking status, hypertension, hypercholesterolemia, and diabetes at baseline, the risk was 8.11-fold higher for patients with quartile 1 than 4 Mg level (95% confidence interval 1.7–38.75; P<0.01). In addition, when tested as a continuous variable, serum magnesium was a significant predictor for MACEs of acute myocardial infarction (HR [per 0.1 mM increase], 0.35 [95% CI, 0.19–0.63], p< 0.01), after adjustment for other confounders.
Low serum level of Mg may be an important predictor of MACEs with DES implantation for acute myocardial infarction. Further research into the effectiveness of Mg supplementation for these patients is warranted.
PMCID: PMC4047047  PMID: 24901943
10.  'Correction:' Serum transforming growth factor beta-1 (TGF-beta-1) levels in diabetic patients are not associated with pre-existent coronary artery disease 
The association between TGF-β1 levels and long-term major adverse cardiovascular events (MACE) in patients with coronary artery disease (CAD) is controversial. No study specifically addressed patients with CAD and diabetes mellitus (DM). The association between TGF-β1 levels and long-term major adverse cardiovascular events (MACE) in patients with coronary artery disease (CAD) is controversial. No study specifically addressed patients with CAD and diabetes mellitus (DM).
Patients (n = 135, 30–80 years) referred for coronary angiography were submitted to clinical and laboratory evaluation, and the coronary angiograms were evaluated by two operators blinded to clinical characteristics. CAD was defined as the presence of a 70% stenosis in one major coronary artery, and DM was characterized as a fasting glycemia > 126 mg/dl or known diabetics (personal history of diabetes or previous use of anti-hyperglycemic drugs or insulin). Based on these criteria, study patients were classified into four groups: no DM and no CAD (controls, C n = 61), DM without CAD (D n = 23), CAD without DM (C-CAD n = 28), and CAD with DM (D-CAD n = 23). Baseline differences between the 4 groups were evaluated by the χ2 test for trend (categorical variables) and by ANOVA (continuous variables, post-hoc Tukey). Patients were then followed-up during two years for the occurrence of MACE (cardiac death, stroke, myocardial infarction or myocardial revascularization). The association of candidate variables with the occurrence of 2-year MACE was assessed by univariate analysis.
The mean age was 58.2 ± 0.9 years, and 51% were men. Patients with CAD had a higher mean age (p = 0.011) and a higher percentage were male (p = 0.040). There were no significant baseline differences between the 4 groups regarding hypertension, smoking status, blood pressure levels, lipid levels or inflammatory markers. TGF-β1 was similar between patients with or without CAD or DM (35.1 ×/÷ 1.3, 33.6 ×/÷ 1.6, 33.9 ×/÷ 1.4 and 31.8 ×/÷ 1.4 ng/ml in C, D, C-CAD and D-CAD, respectively, p = 0.547). In the 2-year follow-ip, independent predictors of 2-year MACE were age (p = 0.007), C-reactive protein (p = 0.048) and systolic blood pressure (p = 0.008), but not TGF-β1.
Serum TGF-β1 was not associated with CAD or MACE occurrence in patients with or without DM.
PMCID: PMC1976604  PMID: 17651487
11.  Effect of Bromocriptine-QR (a Quick-Release Formulation of Bromocriptine Mesylate) on Major Adverse Cardiovascular Events in Type 2 Diabetes Subjects 
Bromocriptine-QR (a quick-release formulation of bromocriptine mesylate), a dopamine D2 receptor agonist, is a US Food and Drug Administrration–approved treatment for type 2 diabetes mellitus (T2DM). A 3070-subject randomized trial demonstrated a significant, 40% reduction in relative risk among bromocriptine-QR-treated subjects in a prespecified composite cardiovascular (CV) end point that included ischemic-related (myocardial infarction and stroke) and nonischemic-related (hospitalization for unstable angina, congestive heart failure [CHF], or revascularization surgery) end points, but did not include cardiovascular death as a component of this composite. The present investigation was undertaken to more critically evaluate the impact of bromocriptine-QR on cardiovascular outcomes in this study subject population by (1) including CV death in the above-described original composite analysis and then stratifying this new analysis on the basis of multiple demographic subgroups and (2) analyzing the influence of this intervention on only the “hard” CV end points of myocardial infarction, stroke, and CV death (major adverse cardiovascular events [MACEs]).
Methods and Results
Three thousand seventy T2DM subjects on stable doses of ≤2 antidiabetes medications (including insulin) with HbA1c ≤10.0 (average baseline HbA1c=7.0) were randomized 2:1 to bromocriptine-QR (1.6 to 4.8 mg/day) or placebo for a 52-week treatment period. Subjects with heart failure (New York Heart Classes I and II) and precedent myocardial infarction or revascularization surgery were allowed to participate in the trial. Study outcomes included time to first event for each of the 2 CV composite end points described above. The relative risk comparing bromocriptine-QR with the control for the cardiovascular outcomes was estimated as a hazard ratio with 95% confidence interval on the basis of Cox proportional hazards regression. The statistical significance of any between-group difference in the cumulative percentage of CV events over time (derived from a Kaplan–Meier curve) was determined by a log-rank test on the intention-to-treat population. Study subjects were in reasonable metabolic control, with an average baseline HbA1c of 7.0±1.1, blood pressure of 128/76±14/9, and total and LDL cholesterol of 179±42 and 98±32, respectively, with 88%, 77%, and 69% of subjects being treated with antidiabetic, antihypertensive, and antihyperlipidemic agents, respectively. Ninety-one percent of the expected person-year outcome ascertainment was obtained in this study. Respecting the CV-inclusive composite cardiovascular end point, there were 39 events (1.9%) among 2054 bromocriptine-QR-treated subjects versus 33 events (3.2%) among 1016 placebo subjects, yielding a significant, 39% reduction in relative risk in this end point with bromocriptine-QR exposure (P=0.0346; log-rank test) that was not influenced by age, sex, race, body mass index, duration of diabetes, or preexisting cardiovascular disease. In addition, regarding the MACE end point, there were 14 events (0.7%) among 2054 bromocriptine-QR-treated subjects and 15 events (1.5%) among 1016 placebo-treated subjects, yielding a significant, 52% reduction in relative risk in this end point with bromocriptine-QR exposure (P<0.05; log-rank test).
These findings reaffirm and extend the original observation of relative risk reduction in cardiovascular adverse events among type 2 diabetes subjects treated with bromocriptine-QR and suggest that further investigation into this impact of bromocriptine-QR is warranted.
Clinical Trial Registration
URL: Unique Identifier: NCT00377676
PMCID: PMC3541616  PMID: 23316290
bromocriptine; circadian rhythm; Cycloset; diabetes mellitus type 2; infarction
12.  Report of the Committee on the Classification and Diagnostic Criteria of Diabetes Mellitus 
Concept of Diabetes Mellitus:
Diabetes mellitus is a group of diseases associated with various metabolic disorders, the main feature of which is chronic hyperglycemia due to insufficient insulin action. Its pathogenesis involves both genetic and environmental factors. The long‐term persistence of metabolic disorders can cause susceptibility to specific complications and also foster arteriosclerosis. Diabetes mellitus is associated with a broad range of clinical presentations, from being asymptomatic to ketoacidosis or coma, depending on the degree of metabolic disorder.
Classification (Tables 1 and 2, and Figure 1):
 Etiological classification of diabetes mellitus and glucose metabolism disorders
Note: Those that cannot at present be classified as any of the above are called unclassifiable.
The occurrence of diabetes‐specific complications has not been confirmed in some of these conditions.
 Diabetes mellitus and glucose metabolism disorders due to other specific mechanisms and diseases
The occurrence of diabetes‐specific complications has not been confirmed in some of these conditions.
 A scheme of the relationship between etiology (mechanism) and patho‐physiological stages (states) of diabetes mellitus. Arrows pointing right represent worsening of glucose metabolism disorders (including onset of diabetes mellitus). Among the arrow lines, indicates the condition classified as ‘diabetes mellitus’. Arrows pointing left represent improvement in the glucose metabolism disorder. The broken lines indicate events of low frequency. For example, in type 2 diabetes mellitus, infection can lead to ketoacidosis and require temporary insulin treatment for survival. Also, once diabetes mellitus has developed, it is treated as diabetes mellitus regardless of improvement in glucose metabolism, therefore, the arrow lines pointing left are filled in black. In such cases, a broken line is used, because complete normalization of glucose metabolism is rare.
The classification of glucose metabolism disorders is principally derived from etiology, and includes staging of pathophysiology based on the degree of deficiency of insulin action. These disorders are classified into four groups: (i) type 1 diabetes mellitus; (ii) type 2 diabetes mellitus; (iii) diabetes mellitus due to other specific mechanisms or diseases; and (iv) gestational diabetes mellitus. Type 1 diabetes is characterized by destruction of pancreatic β‐cells. Type 2 diabetes is characterized by combinations of decreased insulin secretion and decreased insulin sensitivity (insulin resistance). Glucose metabolism disorders in category (iii) are divided into two subgroups; subgroup A is diabetes in which a genetic abnormality has been identified, and subgroup B is diabetes associated with other pathologic disorders or clinical conditions. The staging of glucose metabolism includes normal, borderline and diabetic stages depending on the degree of hyperglycemia occurring as a result of the lack of insulin action or clinical condition. The diabetic stage is then subdivided into three substages: non‐insulin‐ requiring, insulin‐requiring for glycemic control, and insulin‐dependent for survival. The two former conditions are called non‐insulin‐dependent diabetes and the latter is known as insulin‐dependent diabetes. In each individual, these stages may vary according to the deterioration or the improvement of the metabolic state, either spontaneously or by treatment.
Diagnosis (Tables 3–7 and Figure 2):
 Criteria of fasting plasma glucose levels and 75 g oral glucose tolerance test 2‐h value
*Casual plasma glucose ≥200 mg/dL (≥11.1 mmol/L) and HbA1c≥6.5% are also regarded as to indicate diabetic type.
Even for normal type, if 1‐h value is 180 mg/dL (10.0 mmol/L), the risk of progression to diabetes mellitus is greater than for <180 mg/dL (10.0 mmol/L) and should be treated as with borderline type (follow‐up observation, etc.). Fasting plasma glucose level of 100–109 mg/dL (5.5–6.0 mmol/L) is called ‘high‐normal’: within the range of normal fasting plasma glucose.
Plasma glucose level after glucose load in oral glucose tolerance test (OGTT) is not included in casual plasma glucose levels. The value for HbA1c (%) is indicated with 0.4% added to HbA1c (JDS) (%).
 Procedures for diagnosing diabetes mellitus
*The value for HbA1c (%) is indicated with 0.4% added to HbA1c (JDS) (%). **Hyperglycemia must be confirmed in a non‐stressful condition. OGTT, oral glucose tolerance test.
 Disorders and conditions associated with low HbA1c values
 Situations where a 75‐g oral glucose tolerance test is recommended
*The value for HbA1c (%) is indicated with 0.4% added to HbA1c (JDS) (%).
 Definition and diagnostic criteria of gestational diabetes mellitus
(IADPSG Consensus Panel, Reference 42, partly modified with permission of Diabetes Care).
 Flow chart outlining steps in the clinical diagnosis of diabetes mellitus. *The value for HbA1c (%) is indicated with 0.4% added to HbA1c (JDS) (%).
Categories of the State of Glycemia:  Confirmation of chronic hyperglycemia is essential for the diagnosis of diabetes mellitus. When plasma glucose levels are used to determine the categories of glycemia, patients are classified as having a diabetic type if they meet one of the following criteria: (i) fasting plasma glucose level of ≥126 mg/dL (≥7.0 mmol/L); (ii) 2‐h value of ≥200 mg/dL (≥11.1 mmol/L) in 75 g oral glucose tolerance test (OGTT); or (iii) casual plasma glucose level of ≥200 mg/dL (≥11.1 mmol/L). Normal type is defined as fasting plasma glucose level of <110 mg/dL (<6.1 mmol/L) and 2‐h value of <140 mg/dL (<7.8 mmol/L) in OGTT. Borderline type (neither diabetic nor normal type) is defined as falling between the diabetic and normal values. According to the current revision, in addition to the earlier listed plasma glucose values, hemoglobin A1c (HbA1c) has been given a more prominent position as one of the diagnostic criteria. That is, (iv) HbA1c≥6.5% is now also considered to indicate diabetic type. The value of HbA1c, which is equivalent to the internationally used HbA1c (%) (HbA1c [NGSP]) defined by the NGSP (National Glycohemoglobin Standardization Program), is expressed by adding 0.4% to the HbA1c (JDS) (%) defined by the Japan Diabetes Society (JDS).
Subjects with borderline type have a high rate of developing diabetes mellitus, and correspond to the combination of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) noted by the American Diabetes Association (ADA) and WHO. Although borderline cases show few of the specific complications of diabetes mellitus, the risk of arteriosclerosis is higher than those of normal type. When HbA1c is 6.0–6.4%, suspected diabetes mellitus cannot be excluded, and when HbA1c of 5.6–5.9% is included, it forms a group with a high risk for developing diabetes mellitus in the future, even if they do not have it currently.
Clinical Diagnosis:  1 If any of the criteria for diabetic type (i) through to (iv) is observed at the initial examination, the patient is judged to be ‘diabetic type’. Re‐examination is conducted on another day, and if ‘diabetic type’ is reconfirmed, diabetes mellitus is diagnosed. However, a diagnosis cannot be made only by the re‐examination of HbA1c alone. Moreover, if the plasma glucose values (any of criteria [i], [ii], or [iii]) and the HbA1c (criterion [iv]) in the same blood sample both indicate diabetic type, diabetes mellitus is diagnosed based on the initial examination alone. If HbA1c is used, it is essential that the plasma glucose level (criteria [i], [ii] or [iii]) also indicates diabetic type for a diagnosis of diabetes mellitus. When diabetes mellitus is suspected, HbA1c should be measured at the same time as examination for plasma glucose.2 If the plasma glucose level indicates diabetic type (any of [i], [ii], or [iii]) and either of the following conditions exists, diabetes mellitus can be diagnosed immediately at the initial examination.• The presence of typical symptoms of diabetes mellitus (thirst, polydipsia, polyuria, weight loss)• The presence of definite diabetic retinopathy3 If it can be confirmed that the above conditions 1 or 2 existed in the past, diabetes mellitus can be diagnosed or suspected regardless of the current test results.4 If the diagnosis of diabetes cannot be established by these procedures, the patient is followed up and re‐examined after an appropriate interval.5 The physician should assess not only the presence or absence of diabetes, but also its etiology and glycemic stage, and the presence and absence of diabetic complications or associated conditions.
Epidemiological Study:  For the purpose of estimating the frequency of diabetes mellitus, ‘diabetes mellitus’ can be substituted for the determination of ‘diabetic type’ from a single examination. In this case, HbA1c≥6.5% alone can be defined as ‘diabetes mellitus’.
Health Screening:  It is important not to misdiagnose diabetes mellitus, and thus clinical information such as family history and obesity should be referred to at the time of screening in addition to an index for plasma glucose level.
Gestational Diabetes Mellitus:  There are two hyperglycemic disorders in pregnancy: (i) gestational diabetes mellitus (GDM); and (ii) diabetes mellitus. GDM is diagnosed if one or more of the following criteria is met in a 75 g OGTT during pregnancy:
1 Fasting plasma glucose level of ≥92 mg/dL (5.1 mmol/L)2 1‐h value of ≥180 mg/dL (10.0 mmol/L)3 2‐h value of ≥153 mg/dL (8.5 mmol/L)
However, diabetes mellitus that is diagnosed by the clinical diagnosis of diabetes mellitus defined earlier is excluded from GDM. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00074.x, 2010)
PMCID: PMC4020724  PMID: 24843435
Diabetes mellitus; Clinical diagnosis; HbA1c
13.  Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients 
BMJ : British Medical Journal  2002;324(7329):71-86.
To determine the effects of antiplatelet therapy among patients at high risk of occlusive vascular events.
Collaborative meta-analyses (systematic overviews).
Inclusion criteria
Randomised trials of an antiplatelet regimen versus control or of one antiplatelet regimen versus another in high risk patients (with acute or previous vascular disease or some other predisposing condition) from which results were available before September 1997. Trials had to use a method of randomisation that precluded prior knowledge of the next treatment to be allocated and comparisons had to be unconfounded—that is, have study groups that differed only in terms of antiplatelet regimen.
Studies reviewed
287 studies involving 135 000 patients in comparisons of antiplatelet therapy versus control and 77 000 in comparisons of different antiplatelet regimens.
Main outcome measure
“Serious vascular event”: non-fatal myocardial infarction, non-fatal stroke, or vascular death.
Overall, among these high risk patients, allocation to antiplatelet therapy reduced the combined outcome of any serious vascular event by about one quarter; non-fatal myocardial infarction was reduced by one third, non-fatal stroke by one quarter, and vascular mortality by one sixth (with no apparent adverse effect on other deaths). Absolute reductions in the risk of having a serious vascular event were 36 (SE 5) per 1000 treated for two years among patients with previous myocardial infarction; 38 (5) per 1000 patients treated for one month among patients with acute myocardial infarction; 36 (6) per 1000 treated for two years among those with previous stroke or transient ischaemic attack; 9 (3) per 1000 treated for three weeks among those with acute stroke; and 22 (3) per 1000 treated for two years among other high risk patients (with separately significant results for those with stable angina (P=0.0005), peripheral arterial disease (P=0.004), and atrial fibrillation (P=0.01)). In each of these high risk categories, the absolute benefits substantially outweighed the absolute risks of major extracranial bleeding. Aspirin was the most widely studied antiplatelet drug, with doses of 75-150 mg daily at least as effective as higher daily doses. The effects of doses lower than 75 mg daily were less certain. Clopidogrel reduced serious vascular events by 10% (4%) compared with aspirin, which was similar to the 12% (7%) reduction observed with its analogue ticlopidine. Addition of dipyridamole to aspirin produced no significant further reduction in vascular events compared with aspirin alone. Among patients at high risk of immediate coronary occlusion, short term addition of an intravenous glycoprotein IIb/IIIa antagonist to aspirin prevented a further 20 (4) vascular events per 1000 (P<0.0001) but caused 23 major (but rarely fatal) extracranial bleeds per 1000.
Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial disease, or atrial fibrillation. Low dose aspirin (75-150 mg daily) is an effective antiplatelet regimen for long term use, but in acute settings an initial loading dose of at least 150 mg aspirin may be required. Adding a second antiplatelet drug to aspirin may produce additional benefits in some clinical circumstances, but more research into this strategy is needed.
What is already known on this topicAntiplatelet therapy is effective for short term treatment of patients with suspected acute myocardial infarction and unstable anginaLong term treatment is beneficial for patients who have had a myocardial infarction, stroke, or transient ischaemic attackDaily aspirin doses of 75-325 mg are effectiveWhat this study addsAntiplatelet therapy protects against vascular events among patients with stable angina, intermittent claudication, and (if oral anticoagulants are unsuitable) atrial fibrillationAntiplatelet therapy can be started promptly during acute presumed ischaemic stroke and continued long termDaily aspirin doses of 75-150 mg seem to be as effective as higher doses for long term treatments (and clopidrogel is an appropriate alternative for patients with a contraindication to aspirin)Short term addition of a glycoprotein IIb/IIIa antagonist to aspirin prevents vascular events in patients having percutaneous coronary intervention and those with unstable angina but causes increased bleeding
PMCID: PMC64503  PMID: 11786451
14.  Incremental Prognostic Significance of the Elevated Levels of Pentraxin 3 in Patients With Heart Failure With Normal Left Ventricular Ejection Fraction 
Pentraxin 3 (PTX3) is a novel inflammatory marker produced by various cell types including those of the vasculature and the heart. The relationship between inflammatory markers and prognosis of patients with heart failure with normal ejection fraction (HFNEF) remains unknown. We investigated whether plasma PTX3 levels can predict future cardiovascular events in patients with HFNEF.
Methods and Results
Plasma PTX3, high‐sensitivity C‐reactive protein, and B‐type natriuretic peptide levels were measured prospectively in 360 stable patients with HFNEF. The subsequent incidence of cardiovascular events, including cardiovascular death, nonfatal myocardial infarction (MI), unstable angina pectoris, nonfatal ischemic stroke, hospitalization for heart failure decompensation, and coronary revascularization, was determined. During a mean 30‐month follow‐up, 106 patients experienced cardiovascular events. These events were more frequent in patients with high plasma PTX3 levels (>3.0 ng/mL) than low levels (≤3.0 ng/mL). Multivariable Cox hazard analysis showed that PTX3 (hazard ratio: 1.16; 95% CI: 1.05 to 1.27; P<0.01) and B‐type natriuretic peptide (hazard ratio: 1.08; 95% CI: 1.03 to 1.14; P<0.001), but not high‐sensitivity C‐reactive protein levels, were significant predictors of future cardiovascular events. Multivariable Cox analysis with the forced inclusion model, including 5 previously identified prognostic factors, found that PTX3 was a significant predictor of cardiovascular events (hazard ratio: 1.16; 95% CI: 1.06 to 1.27; P<0.01). The C‐statistics for cardiovascular events substantially increased from 0.617 to 0.683 when PTX3 was added to the 5 previously identified prognostic factors.
High plasma PTX3 levels, but not other inflammatory markers, are correlated with future cardiovascular events in patients with HFNEF. PTX3 may be a useful biomarker for assessment of risk stratification in HFNEF.
Clinical Trial Registration
URL:; Unique identifier: UMIN000002170.
PMCID: PMC4310378  PMID: 25012287
cardiovascular events; heart failure with normal ejection fraction; inflammation; left ventricular diastolic dysfunction; pentraxin 3
15.  Heart Failure with Preserved Ejection Fraction: Comparison of Patients With and Without Angina Pectoris (From the Duke Databank for Cardiovascular Disease) 
We aimed to investigate the characteristics and outcomes of patients with heart failure with preserved ejection fraction (HFpEF) and angina pectoris (AP).
AP is a predictor of adverse events in patients with heart failure with reduced EF. The implications of AP in HFpEF are unknown.
We analyzed HFpEF patients (EF≥50%) who underwent coronary angiography at Duke University Medical Center from 2000–2010 with and without AP in the previous 6 weeks. Time to first event was examined using Kaplan-Meier methods for the primary endpoint of death/myocardial infarction (MI)/revascularization/stroke (i.e., MACE) and secondary endpoints of death/MI/revascularization, death/MI/stroke, death/MI, death and cardiovascular death/cardiovascular hospitalization.
In the Duke Databank, 3517 patients met criteria for inclusion and 1402 (40%) had AP. Those with AP were older with more comorbidities, and prior revascularization vs. non-AP patients. AP patients more often received beta-blockers, ACE-inhibitors, nitrates, and statins (all P<0.05). In unadjusted analysis, AP patients had increased MACE and death/MI/revascularization (both P <0.001), lower rates of death and death/MI (both P<0.05), and similar rates of death/MI/stroke and cardiovascular death/cardiovascular hospitalization (both P>0.1). After multivariable adjustment, those with AP remained at increased risk for MACE (Hazard Ratio [HR] 1.30; 95% Confidence Interval [CI], 1.17–1.45) and death/MI/revascularization (HR 1.29; 95% CI, 1.15–1.43), but were at similar risk for other endpoints (P>0.06).
AP in HFpEF patients with a history of coronary artery disease is common despite medical therapy and is independently associated with increased MACE due to revascularization with similar risk of death, MI, and hospitalization.
PMCID: PMC3946907  PMID: 24161322
heart failure with preserved ejection fraction; angina pectoris; outcomes
16.  Predictors of cardiovascular events in a contemporary population with impaired glucose tolerance: an observational analysis of the Nateglinide and Valsartan in impaired glucose tolerance outcomes research (NAVIGATOR) trial 
BMJ Open  2012;2(6):e001925.
Risk factors for cardiovascular events are well established in general populations and those with diabetes but have been sparsely studied in impaired glucose tolerance (IGT). We sought to identify predictors of (1) a composite cardiovascular outcome (cardiovascular death, non-fatal myocardial infarction and non-fatal stroke) and (2) cardiovascular death, among patients with IGT.
We studied participants enrolled in the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. Predictors of cardiovascular events were identified in observational analyses.
Clinical trial participants in 40 countries.
9306 participants with biochemically confirmed IGT at high risk of cardiovascular events participated in NAVIGATOR.
Primary and secondary outcome measures
Cox proportional hazard regression models were constructed using variables (demographic data, medical history, clinical features, biochemical results and ECG findings) recorded at baseline to identify variables associated with and predictive of cardiovascular events.
Over 6.4 years, 639 (6.9%) participants experienced a cardiovascular event, and 244 (2.6%) cardiovascular death. While predictors of both outcomes included established risk factors such as existing cardiovascular disease, male gender, older age, current smoking status and higher low-density lipoprotein cholesterol, other variables such as reduced estimated glomerular filtration rate, previous thromboembolic disease, atrial fibrillation, higher urinary albumin/creatinine ratio and chronic obstructive pulmonary disease were also important predictors. Glycaemic measures were not predictive of cardiovascular events. c-Statistics for predicting cardiovascular events and cardiovascular death were 0.74 and 0.82, respectively. This compares with c-statistics for cardiovascular events and cardiovascular death of 0.65 and 0.71, respectively, using the classical Framingham risk factors of age, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, treatment for hypertension and smoking status.
The most powerful independent predictors of cardiovascular events in IGT included both established risk factors and other variables excluding measures of glycaemia, allowing effective identification of high-risk individuals.
PMCID: PMC3533049  PMID: 23204139
17.  Predictors of risk in patients with unstable angina admitted to a district general hospital. 
British Heart Journal  1992;67(5):395-401.
OBJECTIVE--To observe the long-term prognosis of patients with unstable angina and select simple criteria to identify high and low risk subgroups. DESIGN--A six month prospective survey with three year follow up. SETTING--One eleven bed coronary care unit. PATIENTS--All patients admitted with chest pain in whom no infarct was confirmed by subsequent electrocardiographic or enzyme changes and for whom no alternative cause of chest pain was found were studied. Unstable angina was also diagnosed if there was evidence of myocardial ischaemia in the form of previous effort angina, previous myocardial infarction, or if transient electrocardiographic changes accompanied the pain. When none of the above were present, chest pain without a known cause, was diagnosed. INTERVENTIONS--No routine intervention. Angiography and revascularisation for persistent symptoms despite medical treatment. OUTCOME MEASURES--Death or non-fatal infarction. RESULTS--In the 141 patients with unstable angina there were eight deaths and five non-fatal infarctions during the first eight weeks. Symptoms of increasing angina before admission were similar in all three groups and did not help predict early complications. Recurrence of pain in hospital, a rise in cardiac enzymes to less than twice the upper limit of normal, and transient electrocardiographic changes were all associated with an increased risk of early events. The presence of either abnormal enzyme activity or more than five episodes of pain in hospital identified a group of 49 in whom 11 of the 13 early events occurred. After three years, 29 of the 141 patients had died and eight had had infarctions (overall event rate 26%). Seventeen had undergone revascularisation (12%) and 51 (36%) were on antianginal treatment. Thirty six (26%) were still alive, without new myocardial infarction, and were free of angina. In the 29 patients with chest pain without a known cause there were no early events and only one non-fatal infarction during the three year follow up. CONCLUSION--When patients are admitted to the coronary care unit with chest pain not due to myocardial infarction, the history, electrocardiography and measurement of cardiac enzymes are sufficient to identify high and low risk subgroups.
PMCID: PMC1024862  PMID: 1389720
18.  Antioxidative vitamines for prevention of cardiovascular disease for patients after renal transplantation and patients with chronic renal failure  
The mortality from cardiovascular disease in patients with chronic renal failure is much higher than in the general population. In particular, patients with chronic renal failure with replacement therapies (dialysis patients and patients with renal transplantation) show both increased traditional risk factors and risk factors due to the dysfunction of the renal system. In combination with necessary medication for renal insufficiency oxidative stress is elevated. Progression of atherosclerosis is promoted due to increased oxidation of lipids and endothelium damage. This link between lipid oxidation and artherogenesis provides the rationale for the supposed beneficial effect of supplementation with antioxidative vitamins (vitamin A, C and E). Such an effect could not be demonstrated for patients with a history of cardiovascular disease and without kidney diseases. However, in high risk patients with chronic renal failure and renal replacement therapies this could be different.
The objective of this systematic literature review was to assess the clinical effectiveness and cost-effectiveness of supplementation with antioxidative vitamins A, C or E to reduce cardiovascular events in patients with chronic kidney diseases, dialysis-requiring patients and patients after a renal transplantation with or without cardiovascular diseases.
A systematic literature review was conducted with documented search and selection of the literature, using a priori defined inclusion and exclusion criteria as well as a documented extraction and assessment of the literature according to the methods of evidence-based medicine.
21 publications met the inclusion criteria for the evaluation of clinical effectiveness. No study could be identified for the economic evaluation. Two studies (four publications) analysed the effect of oral supplementation on the secondary prevention of clinical cardiovascular endpoints. Studies analysing the effect on patients without a history of cardiovascular disease could not be identified. 17 studies analysed the effect of oral supplementation or infusion with antioxidative vitamins or the supplementation with dialysis membranes coated with vitamin E on intermediate outcomes like oxidative stress or vessel parameters.
The two randomized clinical trials analysing the effect of orally supplemented vitamin E on clinical endpoints in patients with mild-to-moderate renal insufficiency and for haemodialysis patients respectively reported different results. After 4.5 years supplementation with a daily dose of 400 IU vitamin E renal insufficiency patients showed neither a beneficial nor a harmful effect on a combined event rate of myocardial infarction, stroke or death by cardiovascular causes. The second study reported a 50% risk reduction (RR=0.46, 95%-KI: 0.27-0.78, p=0.014) on the combined event rate of fatal myocardial infarction, nonfatal myocardial infarction, stroke, peripheral vascular disease or unstable angina pectoris in the study arm with vitamin E-Supplementation of 800 IU daily.
In 16 of 17 studies with intermediate endpoints the supplementation with vitamins was associated with a change of one or several of the examined endpoints in the expected direction. This means that the concentrations of the markers for oxidative stress decreased in the Vitamin E-group, the progression of aortic calcification (only one study) was reduced, the intima media thickness decreased and the lipid profile improved. No studies regarding costs or cost-effectiveness were identified.
A possible explanation for the different results in the two studies with clinical endpoints may be due to the different study populations with different risk profiles, to different dosage during the intervention or to variation by chance. Due to the absence of clinically meaningful endpoints, the relevance of studies analysing the effect of antioxidative vitamins on intermediate endpoints like oxidative stress markers is basically limited to show single intermediate steps of the postulated biological effect mechanisms by which a potentially preventive effect could possibly be mediated. The mainly unsatisfactory planning and reporting quality of the 17 identified studies and a possible "publication bias" are further limitations.
The available evidence is not sufficient to support or to reject an effect of antioxidative vitamins on secondary prevention for cardiovascular disease for patients with chronic renal insufficiency or renal replacement therapy. There is a lack of randomized, placebo-controlled studies with a sufficient number of cases and clinical endpoints of cardiovascular disease, on the effect of antioxidative vitamins either orally applied or given by vitamin E-modified dialysers.
No data are available about supplementation with antioxidative vitamins for primary prevention of cardiovascular disease. Therefore the current evidence does not allow to draw conclusions concerning this subject either. As opposed to patients with a history of cardiovascular disease without kidney diseases where there is enough evidence to exclude a beneficial effect on secondary prevention of cardiovascular disease for patients with chronic renal insufficiency and renal replacement therapy this question remains unanswered. Conclusions about costs and cost-effectiveness also cannot be drawn.
PMCID: PMC3011345  PMID: 21289965
19.  Reduced Glomerular Filtration Rate and Its Association with Clinical Outcome in Older Patients at Risk of Vascular Events: Secondary Analysis 
PLoS Medicine  2009;6(1):e1000016.
Reduced glomerular filtration rate (GFR) is associated with increased cardiovascular risk in young and middle aged individuals. Associations with cardiovascular disease and mortality in older people are less clearly established. We aimed to determine the predictive value of the GFR for mortality and morbidity using data from the 5,804 participants randomized in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER).
Methods and Findings
Glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation and was categorized in the ranges ([20–40], [40–50], [50–60]) ≥ 60 ml/min/1.73 m2. Baseline risk factors were analysed by category of eGFR, with and without adjustment for other risk factors. The associations between baseline eGFR and morbidity and mortality outcomes, accrued after an average of 3.2 y, were investigated using Cox proportional hazard models adjusting for traditional risk factors. We tested for evidence of an interaction between the benefit of statin treatment and baseline eGFR status. Age, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), body mass index, fasting glucose, female sex, histories of hypertension and vascular disease were associated with eGFR (p = 0.001 or less) after adjustment for other risk factors. Low eGFR was independently associated with risk of all cause mortality, vascular mortality, and other noncancer mortality and with fatal and nonfatal coronary and heart failure events (hazard ratios adjusted for CRP and other risk factors (95% confidence intervals [CIs]) for eGFR < 40 ml/min/1.73m2 relative to eGFR ≥ 60 ml/min/1.73m2 respectively 2.04 (1.48–2.80), 2.37 (1.53–3.67), 3.52 (1.78–6.96), 1.64 (1.18–2.27), 3.31 (2.03–5.41). There were no nominally statistically significant interactions (p < 0.05) between randomized treatment allocation and eGFR for clinical outcomes, with the exception of the outcome of coronary heart disease death or nonfatal myocardial infarction (p = 0.021), with the interaction suggesting increased benefit of statin treatment in subjects with impaired GFRs.
We have established that, in an elderly population over the age of 70 y, impaired GFR is associated with female sex, with presence of vascular disease, and with levels of other risk factors that would be associated with increased risk of vascular disease. Further, impaired GFR is independently associated with significant levels of increased risk of all cause mortality and fatal vascular events and with composite fatal and nonfatal coronary and heart failure outcomes. Our analyses of the benefits of statin treatment in relation to baseline GFR suggest that there is no reason to exclude elderly patients with impaired renal function from treatment with a statin.
Using data from the PROSPER trial, Ian Ford and colleagues investigate whether reduced glomerular filtration rate is associated with cardiovascular and mortality risk among elderly people.
Editors' Summary
Cardiovascular disease (CVD)—disease that affects the heart and/or the blood vessels—is a common cause of death in developed countries. In the USA, for example, the single leading cause of death is coronary heart disease, a CVD in which narrowing of the heart's blood vessels slows or stops the blood supply to the heart and eventually causes a heart attack. Other types of CVD include stroke (in which narrowing of the blood vessels interrupts the brain's blood supply) and heart failure (a condition in which the heart can no longer pump enough blood to the rest of the body). Many factors increase the risk of developing CVD, including high blood pressure (hypertension), high blood cholesterol, having diabetes, smoking, and being overweight. Tools such as the “Framingham risk calculator” assess an individual's overall CVD risk by taking these and other risk factors into account. CVD risk can be minimized by taking drugs to reduce blood pressure or cholesterol levels (for example, pravastatin) and by making lifestyle changes.
Why Was This Study Done?
Another potential risk factor for CVD is impaired kidney (renal) function. In healthy people, the kidneys filter waste products and excess fluid out of the blood. A reduced “estimated glomerular filtration rate” (eGFR), which indicates impaired renal function, is associated with increased CVD in young and middle-aged people and increased all-cause and cardiovascular death in people who have vascular disease. But is reduced eGFR also associated with CVD and death in older people? If it is, it would be worth encouraging elderly people with reduced eGFR to avoid other CVD risk factors. In this study, the researchers determine the predictive value of eGFR for all-cause and vascular mortality (deaths caused by CVD) and for incident vascular events (a first heart attack, stroke, or heart failure) using data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). This clinical trial examined pravastatin's effects on CVD development among 70–82 year olds with pre-existing vascular disease or an increased risk of CVD because of smoking, hypertension, or diabetes.
What Did the Researchers Do and Find?
The trial participants were divided into four groups based on their eGFR at the start of the study. The researchers then investigated the association between baseline CVD risk factors and baseline eGFR and between baseline eGFR and vascular events and deaths that occurred during the 3-year study. Several established CVD risk factors were associated with a reduced eGFR after allowing for other risk factors. In addition, people with a low eGFR (between 20 and 40 units) were twice as likely to die from any cause as people with an eGFR above 60 units (the normal eGFR for a young person is 100 units; eGFR decreases with age) and more than three times as likely to have nonfatal coronary heart disease or heart failure. A low eGFR also increased the risk of vascular mortality, other noncancer deaths, and fatal coronary heart disease and heart failure. Finally, pravastatin treatment reduced coronary heart disease deaths and nonfatal heart attacks most effectively among participants with the greatest degree of eGFR impairment.
What Do These Findings Mean?
These findings suggest that, in elderly people, impaired renal function is associated with levels of established CVD risk factors that increase the risk of vascular disease. They also suggest that impaired kidney function increases the risk of all-cause mortality, fatal vascular events, and fatal and nonfatal coronary heat disease and heart failure. Because the study participants were carefully chosen for inclusion in PROSPER, these findings may not be generalizable to all elderly people with vascular disease or vascular disease risk factors. Nevertheless, increased efforts should probably be made to encourage elderly people with reduced eGFR and other vascular risk factors to make lifestyle changes to reduce their overall CVD risk. Finally, although the effect of statins in elderly patients with renal dysfunction needs to be examined further, these findings suggest that this group of patients should benefit at least as much from statins as elderly patients with healthy kidneys.
Additional Information.
Please access these Web sites via the online version of this summary at
The MedlinePlus Encyclopedia has pages on coronary heart disease, stroke, and heart failure (in English and Spanish)
MedlinePlus provides links to many other sources of information on heart disease, vascular disease, and stroke (in English and Spanish)
The US National Institute of Diabetes and Digestive and Kidney Diseases provides information on how the kidneys work and what can go wrong with them, including a list of links to further information about kidney disease
The American Heart Association provides information on all aspects of cardiovascular disease for patients, caregivers, and professionals (in several languages)
More information about PROSPER is available on the Web site of the Vascular Biochemistry Department of the University of Glasgow
PMCID: PMC2628400  PMID: 19166266
20.  Risk score for predicting death, myocardial infarction, and stroke in patients with stable angina, based on a large randomised trial cohort of patients 
BMJ : British Medical Journal  2005;331(7521):869.
Objective To derive a risk score for the combination of death from all causes, myocardial infarction, and disabling stroke in patients with stable symptomatic angina who require treatment for angina and have preserved left ventricular function.
Design Multivariate Cox regression analysis of data from a large multicentre trial.
Setting Outpatient cardiology clinics in western Europe, Israel, Canada, Australia, and New Zealand.
Participants 7311 patients with all required data available.
Main outcome measure Death from any cause or myocardial infarction or disabling stroke during a mean follow-up of 4.9 years.
Results 1063 patients either died from any cause or sustained myocardial infarction or disabling stroke. The five year risk of this composite ranged from 4% for patients in the lowest tenth of risk to 35% for patients in the highest tenth. The risk score combines 16 routinely available clinical variables (in order of decreasing contribution): age, left ventricular ejection fraction, smoking, white blood cell count, diabetes, casual blood glucose concentration, creatinine concentration, previous stroke, at least one angina attack a week, coronary angiographic findings (if available), lipid lowering treatment, QT interval, systolic blood pressure ≥ 155 mm Hg, number of drugs used for angina, previous myocardial infarction, and sex. Fitting the same model separately to all cause death, myocardial infarction, and stroke gave similar results. The risk score did not seem to predict the nature of the event (death in 39%, myocardial infarction in 46%, and disabling stroke in 15%) or the incidence of angiography or revascularisation, which occurred in 29% of patients.
Conclusion This risk score is an objective aid in deciding on further management of patients with stable angina with the aim of reducing serious outcome events. The score can also be used in planning future trials.
PMCID: PMC1255789  PMID: 16210253
21.  Predictive Value of Brachial Flow-Mediated Dilation for Incident Cardiovascular Events in a Population-Based Study: The Multi-Ethnic Study of Atherosclerosis 
Circulation  2009;120(6):502-509.
Although brachial artery flow-mediated dilation (FMD) predicts recurrent cardiovascular events, its predictive value for incident cardiovascular disease (CVD) events in adults free of CVD is not well established. We assessed the predictive value of FMD for incident CVD events in the Multi Ethnic Study of Atherosclerosis (MESA).
Methods and Results
Brachial artery FMD was measured in a nested case- cohort sample of 3026 out of 6814 subjects (mean ± SD age 61.2 ± 9.9 years), in MESA, a population-based cohort study of adults free of clinical CV disease at baseline recruited at six clinic sites in the USA. The sample comprised 50.2% females, 34.3% Caucasian, 19.7% Chinese, 20.8% African Americans and 25.1% Hispanics. Probability-weighted Cox proportional hazard analysis was used to examine the association between FMD and five years of adjudicated incident CVD events, including incident myocardial infarction, definite angina, coronary revascularization (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty or other revascularization), stroke, resuscitated cardiac arrest and CVD death.
Mean (SD) FMD of the cohort was 4.4 (2.8) %. In probability-weighted Cox models, FMD/unit SD was significantly associated with incident cardiovascular events in both the univariate(adjusted for age and gender) [hazard ratio; 0.79(95% CI, 0.65–0.97), p=0.01], after adjusting for the Framingham Risk Score (FRS) [hazard ratio; 0.80(95%CI, 0.62–0.97), p=0.025] and also in multivariable models [hazard ratio; 0.84(95%CI, 0.71–0.99), p=0.04] after adjusting for age, gender, diabetes mellitus, cigarette smoking status, systolic blood pressure, HDL, LDL, triglycerides, heart rate, statin use and blood pressure medication use. The c statistic (AUC) of FMD, FRS, FRS + FMD) were 0.65, 0.74 and 0.74 respectively. Compared with the FRS alone, the addition of FMD to the FRS net correctly re-classifies 52% of subjects with no incident CVD event, but net incorrectly reclassifies 23% of subjects with an incident CVD event; an overall net correct re-classification of 29% (p < 0.001).
Brachial FMD is a predictor of incident cardiovascular events in population based adults. Even though the addition of FMD to the FRS did not improve discrimination of subjects at risk of CVD events in ROC analysis, it did improve the classification of subjects as low, intermediate and high CVD risk compared to the FRS.
PMCID: PMC2740975  PMID: 19635967
Endothelial dysfunction; brachial flow-mediated dilation; incident cardiovascular event; healthy adults
22.  Postchallenge responses of nitrotyrosine and TNF-alpha during 75-g oral glucose tolerance test are associated with the presence of coronary artery diseases in patients with prediabetes 
Meta-analysis has demonstrated an exponential relationship between 2-hr postchallenge hyperglycemia and coronary artery disease (CAD). Pulsatile hyperglycemia can acutely increase proinflammatory cytokines by oxidative stress. We hypothesized that postchallenge proinflammatory and nitrosative responses after 75 g oral glucose tolerance tests (75 g-OGTT) might be associated with CAD in patients without previously recognized type 2 diabetes mellitus (T2DM).
Serial changes of plasma glucose (PG), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nitrotyrosine levels were analyzed during 75 g-OGTT in 120 patients (81 male; age 62 ± 11 years) before coronary angiography. Patients were classified as normal (NGT; 42%), impaired (IGT; 34%) and diabetic (T2DM; 24%) glucose tolerance by 75 g-OGTT.
Postchallenge hyperglycemia elicited TNF-α, IL-6 and nitrotyrosine levels time-dependently, and 2-hr median levels of TNF-α (7.1 versus 6.4 pg/ml; P < 0.05) and nitrotyrosine (1.01 versus 0.83 μmol/l; P < 0.05), but not IL-6 or PG, were significantly higher in patients with CAD in either IGT or T2DM groups. After adjusting risk factors and glucose tolerance status, 2-hr nitrotyrosine in highest quartiles (OR: 3.1, P < 0.05) remained an independent predictor of CAD by logistic regression analysis.
These results highlight postchallenge proinflammatory and nitrosative responses by 75 g-OGTT, rather than hyperglycemia per se, are associated with CAD in patients without previous recognized diabetes.
PMCID: PMC3316140  PMID: 22397368
Postchallenge hyperglycemia; Inflammation; Oxidative stress; Nitrotyrosine oral; Glucose tolerance test; Coronary artery disease
23.  Abnormal glucose regulation in patients with acute ST- elevation myocardial infarction-a cohort study on 224 patients 
A high prevalence of impaired glucose tolerance and unknown type 2-diabetes in patients with coronary heart disease and no previous diagnosis of diabetes have been reported. The aims of the present study were to investigate the prevalence of abnormal glucose regulation (AGR) 3 months after an acute ST-elevation myocardial infarction (STEMI) in patients without known glucometabolic disturbance, to evaluate the reliability of a 75-g oral glucose tolerance test (OGTT) performed very early after an acute STEMI to predict the presence of AGR at 3 months, and to study other potential predictors measured in-hospital for AGR at 3 months.
This was an observational cohort study prospectively enrolling 224 STEMI patients treated with primary PCI. An OGTT was performed very early after an acute STEMI and was repeated in 200 patients after 3 months. We summarised the exact agreement observed, and assessed the observed reproducibility of the OGTTs performed in-hospital and at follow up. The patients were classified into glucometabolic categories defined according to the World Health Organisation criteria. AGR was defined as the sum of impaired fasting glucose, impaired glucose tolerance and type 2-diabetes.
The prevalence of AGR at three months was 24.9% (95% CI 19.1, 31.4%), reduced from 46.9% (95% CI 40.2, 53.6) when measured in-hospital. Only, 108 of 201 (54%) patients remained in the same glucometabolic category after a repeated OGTT. High levels of HbA1c and admission plasma glucose in-hospital significantly predicted AGR at 3 months (p < 0.001, p = 0.040, respectively), and fasting plasma glucose was predictive when patients with large myocardial infarction were excluded (p < 0.001).
The prevalence of AGR in STEMI patients was lower than expected. HbA1c, admission plasma glucose and fasting plasma glucose measured in-hospital seem to be useful as early markers of longstanding glucometabolic disturbance. An OGTT performed very early after a STEMI did not provide reliable information on long-term glucometabolic state and should probably not be recommended.
PMCID: PMC2646717  PMID: 19183453
24.  Impact of timing to coronary angiography in acute coronary syndrome on contemporary clinical practice 
Recent studies appear to suggest a correlation between timing to coronary angiography and clinical outcome among patients with acute coronary syndrome (ACS). We aim to study 12-month outcomes of ACS patients who are stratified according to early (≤24 hours), intermediate (>24 to <48 hours) and delayed (≥48 hours) coronary angiography. This is a prospective observational study of patients with ACS defined as either unstable angina pectoris or non-ST elevation myocardial infarction (MI) admitted between October 2008 and July 2009. Baseline clinical characteristics of age, gender, cardiovascular risk factors (diabetes mellitus, hypertension, dyslipidemia) and TIMI score were analyzed and adjusted for outcomes. The primary outcome was combined major adverse cardiovascular events (MACE) of death or non-fatal MI, as well as target vessel revascularization (TVR) up to 12 months. This study consisted of 642 patients (75% males, mean age 60±13) with median follow-up of 7 months and median TIMI score of 4. Over half (50.2%) were categorized as high-risk (TIMI score ≥4). 281 patients (43.5%) had early angiography, 170 (26.5%) had angiography between >24 to <48 hours and 191(30%) patients had delayed angiography ≥48 hours. In high-risk patients, the primary outcome occurred in 10.9% of patients in the early group, as compared with 13.2% in intermediate group and 23.9% in delayed group (p=0.015) at six months. However, in low-risk patients (TIMI scores <4), there was no significant difference between the groups (7.1% vs. 3.4% vs. 5.9%, p=0.316) at six months. Compared to the intermediate and delayed groups, patients in the early group had lower overall MACE at 12 months (21% vs. 14% vs. 10%, p=0.006) that was largely related to a lower frequency of death at 12 months (11% vs. 7% vs. 4.6%, p=0.03). There were no differences in rates of TVR between the groups (4% vs. 7% vs. 3.5%, p=0.14). In this observational analysis, an early strategy to coronary angiography was associated with improved survival at one year while an early to intermediate strategy benefitted the subgroup of high-risk patients with significant reductions in cardiovascular events at six months.
PMCID: PMC3427977  PMID: 22937494
Myocardial infarction; acute coronary syndrome; coronary angiography
25.  Reappraisal of Metformin Efficacy in the Treatment of Type 2 Diabetes: A Meta-Analysis of Randomised Controlled Trials 
PLoS Medicine  2012;9(4):e1001204.
Catherine Cornu and colleagues performed a meta-analysis of randomised controlled trials of metformin efficacy on cardiovascular morbidity or mortality in patients with type 2 diabetes and showed that although metformin is considered the gold standard, its benefit/risk ratio remains uncertain.
The UK Prospective Diabetes Study showed that metformin decreases mortality compared to diet alone in overweight patients with type 2 diabetes mellitus. Since then, it has been the first-line treatment in overweight patients with type 2 diabetes. However, metformin-sulphonylurea bitherapy may increase mortality.
Methods and Findings
This meta-analysis of randomised controlled trials evaluated metformin efficacy (in studies of metformin versus diet alone, versus placebo, and versus no treatment; metformin as an add-on therapy; and metformin withdrawal) against cardiovascular morbidity or mortality in patients with type 2 diabetes. We searched Medline, Embase, and the Cochrane database. Primary end points were all-cause mortality and cardiovascular death. Secondary end points included all myocardial infarctions, all strokes, congestive heart failure, peripheral vascular disease, leg amputations, and microvascular complications. Thirteen randomised controlled trials (13,110 patients) were retrieved; 9,560 patients were given metformin, and 3,550 patients were given conventional treatment or placebo. Metformin did not significantly affect the primary outcomes all-cause mortality, risk ratio (RR) = 0.99 (95% CI: 0.75 to 1.31), and cardiovascular mortality, RR = 1.05 (95% CI: 0.67 to 1.64). The secondary outcomes were also unaffected by metformin treatment: all myocardial infarctions, RR = 0.90 (95% CI: 0.74 to 1.09); all strokes, RR = 0.76 (95% CI: 0.51 to 1.14); heart failure, RR = 1.03 (95% CI: 0.67 to 1.59); peripheral vascular disease, RR = 0.90 (95% CI: 0.46 to 1.78); leg amputations, RR = 1.04 (95% CI: 0.44 to 2.44); and microvascular complications, RR = 0.83 (95% CI: 0.59 to 1.17). For all-cause mortality and cardiovascular mortality, there was significant heterogeneity when including the UK Prospective Diabetes Study subgroups (I2 = 41% and 59%). There was significant interaction with sulphonylurea as a concomitant treatment for myocardial infarction (p = 0.10 and 0.02, respectively).
Although metformin is considered the gold standard, its benefit/risk ratio remains uncertain. We cannot exclude a 25% reduction or a 31% increase in all-cause mortality. We cannot exclude a 33% reduction or a 64% increase in cardiovascular mortality. Further studies are needed to clarify this situation.
Please see later in the article for the Editors' Summary
Editors' Summary
Worldwide, more than 350 million people have diabetes, and this number is increasing rapidly. Diabetes is characterized by dangerous amounts of sugar (glucose) in the blood. Blood sugar levels are normally controlled by insulin, a hormone produced by the pancreas. In people with type 2 diabetes (the most common form of diabetes), blood sugar control fails because the fat and muscle cells that usually respond to insulin by removing excess sugar from the blood become less responsive to insulin. Type 2 diabetes can be controlled with diet and exercise and with antidiabetic pills, each of which works in a different way to maintain a healthy blood sugar level. Metformin, for example, stops the liver making glucose and increases the body's response to insulin, whereas sulfonylureas help the pancreas make more insulin. The long-term complications of diabetes, which include an increased risk of cardiovascular problems such as heart disease and stroke, reduce the life expectancy of people with diabetes by about ten years compared to people without diabetes.
Why Was This Study Done?
In 1998, a large randomized clinical trial called the UK Prospective Diabetes Study (UKPDS 34) reported that metformin in combination with dietary control reduced all-cause mortality in overweight patients with type 2 diabetes when compared to dietary control alone. Specifically, the risk of death from any cause among patients taking metformin was about a third lower than the risk of death among patients not taking metformin—a risk ratio (RR) of 0.64. This reduction in risk was significant (that is, it was unlikely to have occurred by chance) because its 95% confidence interval (95% CI; there is a 95% chance that the “true” RR lies within this interval) of 0.45–0.91 did not overlap 1.0. Given this finding, metformin is now recommended as the first-line treatment for type 2 diabetes. However, UKPDS 34 also reported an increase in death in non-overweight patients who took metformin plus sulfonylurea compared to those who took sulfonylurea alone (RR: 1.60; 95% CI: 1.02–2.52), a result considered non-significant by the UKPDS 34 researchers and largely ignored ever since. So do the benefits of metformin outweigh its risks? In this meta-analysis, the researchers re-evaluate the risk-to-benefit balance of metformin in the treatment of patients with type 2 diabetes. A meta-analysis is a statistical method that combines the results of several studies.
What Did the Researchers Do and Find?
The researchers identified 13 randomized controlled trials that evaluated the effect of metformin on cardiovascular morbidity (illness) and mortality in patients with type 2 diabetes. More than 13,000 patients participated in these studies, three-quarters of whom received metformin and a quarter of whom received other treatments or a placebo. Compared to other treatments, metformin treatment had no effect on the risk of all-cause mortality (RR: 0.99; 95% CI: 0.75–1.31) or cardiovascular mortality (RR: 1.05; 95% CI: 0.67–1.64), the primary end points of this study. However, the results of the individual trials varied more than would be expected by chance (“heterogeneity”). Exclusion of the UKPDS 34 trial from the meta-analysis had no effect on the estimated risk ratio for all-cause mortality or cardiovascular deaths, but the heterogeneity disappeared. Finally, metformin treatment had no significant effect on the risk of cardiovascular conditions such as heart attacks, strokes, and heart failure; there was no heterogeneity among the trials for these secondary end points.
What Do These Findings Mean?
These findings show no evidence that metformin has any beneficial effect on all-cause mortality, on cardiovascular mortality, or on cardiovascular morbidity among patients with type 2 diabetes. These findings must be cautiously interpreted because only a few randomized controlled trials were included in this study, and only a few patients died or developed any cardiovascular illnesses. Importantly, however, from these findings, it is impossible to exclude beyond reasonable doubt the possibility that metformin causes up to a 25% reduction or a 31% increase in all-cause mortality. Similarly, these findings cannot exclude the possibility that metformin causes up to a 33% reduction or a 64% increase in cardiovascular mortality. Given that a large number of patients take metformin for many years as a first-line treatment for diabetes, further studies are urgently needed to clarify this situation.
Additional Information
Please access these web sites via the online version of this summary at
The International Diabetes Federation provides information about all aspects of diabetes
The US National Diabetes Information Clearinghouse provides information about diabetes for patients, health-care professionals, and the general public, including detailed information on diabetes medicines (in English and Spanish)
The UK National Health Service Choices web site provides information for patients and carers about type 2 diabetes and includes peoples stories about diabetes
The charity Diabetes UK also provides detailed information for patients and carers, including information on diabetes medications, and has a further selection of stories from people with diabetes
MedlinePlus provides links to further resources and advice about diabetes and about diabetes medicines; it also provides information about metformin (in English and Spanish)
The charity Healthtalkonline has interviews with people about their experiences of diabetes and of controlling diabetes with oral medications
PMCID: PMC3323508  PMID: 22509138

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