Although observational evidence has suggested that the measurement of CAC may improve risk stratification for cardiovascular events and thus help guide the use of lipid-lowering therapy, this contention has not been evaluated within the context of a randomized trial. The Value of Imaging in Enhancing the Wellness of Your Heart (VIEW) trial is proposed as a randomized study in participants at low intermediate risk of future coronary heart disease (CHD) events to evaluate whether coronary artery calcium (CAC) testing leads to improved patient outcomes.
To describe the challenges encountered in designing a prototypical screening trial and to examine the impact of uncertainty on power.
The VIEW trial was designed as an effectiveness clinical trial to examine the benefit of CAC testing to guide therapy on a primary outcome consisting of a composite of non-fatal myocardial infarction, probable or definite angina with revascularization, resuscitated cardiac arrest, non-fatal stroke (not transient ischemic attack (TIA)), CHD death, stroke death, other atherosclerotic death, or other cardiovascular disease (CVD) death. Many critical choices were faced in designing the trial, including: (1) the choice of primary outcome, (2) the choice of therapy, (3) the target population with corresponding ethical issues, (4) specifications of assumptions for sample size calculations, and (5) impact of uncertainty in these assumptions on power/sample size determination.
We have proposed a sample size of 30,000 (800 events) which provides 92.7% power. Alternatively, sample sizes of 20,228 (539 events), 23,138 (617 events) and 27,078 (722 events) provide 80, 85, and 90% power. We have also allowed for uncertainty in our assumptions by computing average power integrated over specified prior distributions. This relaxation of specificity indicates a reduction in power, dropping to 89.9% (95% confidence interval (CI): 89.8 to 89.9) for a sample size of 30,000. Samples sizes of 20,228, 23,138, and 27,078 provide power of 78.0% (77.9 to 78.0), 82.5% (82.5 to 82.6), and 87.2% (87.2 to 87.3), respectively.
These power estimates are dependent on form and parameters of the prior distributions.
Despite the pressing need for a randomized trial to evaluate the utility of CAC testing, conduct of such a trial requires recruiting a large patient population, making efficiency of critical importance. The large sample size is primarily due to targeting a study population at relatively low risk of a CVD event. Our calculations also illustrate the importance of formally considering uncertainty in power calculations of large trials as standard power calculations may tend to overestimate power.
cardiovascular disease (CVD); coronary heart disease (CHD); coronary artery calcium (CAC); disease prevention; statistical power; Bayes
To compare effects of combinations of standard and intensive treatment of glycemia and either blood pressure (BP) or lipids in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial.
RESEARCH DESIGN AND METHODS
ACCORD enrolled 10,251 type 2 diabetes patients aged 40–79 years at high risk for cardiovascular disease (CVD) events. Participants were randomly assigned to hemoglobin A1c goals of <6.0% (<42 mmol/mol; intensive glycemia) or 7.0–7.9% (53–63 mmol/mol; standard glycemia) and then randomized a second time to either 1) systolic BP goals of <120 mmHg (intensive BP) or <140 mmHg (standard BP) or 2) simvastatin plus fenofibrate (intensive lipid) or simvastatin plus placebo (standard lipid). Proportional hazards models were used to assess combinations of treatment assignments on the composite primary (deaths due to CVD, nonfatal myocardial infarction [MI], and nonfatal stroke) and secondary outcomes.
In the BP trial, risk of the primary outcome was lower in the groups intensively treated for glycemia (hazard ratio [HR] 0.67; 95% CI 0.50–0.91), BP (HR 0.74; 95% CI 0.55–1.00), or both (HR 0.71; 95% CI 0.52–0.96) compared with combined standard BP and glycemia treatment. For secondary outcomes, MI was significantly reduced by intensive glycemia treatment and stroke by intensive BP treatment; most other HRs were neutral or favored intensive treatment groups. In the lipid trial, the general pattern of results showed no evidence of benefit of intensive regimens (whether single or combined) compared with combined standard lipid and glycemia treatment. The mortality HR was 1.33 (95% CI 1.02–1.74) in the standard lipid/intensive glycemia group compared with the standard lipid/standard glycemia group.
In the ACCORD BP trial, compared with combined standard treatment, intensive BP or intensive glycemia treatment alone improved major CVD outcomes, without additional benefit from combining the two. In the ACCORD lipid trial, neither intensive lipid nor glycemia treatment produced an overall benefit, but intensive glycemia treatment increased mortality.
To evaluate associations of early menopause (menopause occurring before 45 years of age) and age at menopause with incident heart failure (HF) in post-menopausal women. We also explored associations of early, and age at menopause with left ventricular (LV) measures of structure and function in post-menopausal women.
We included 2947 post-menopausal women, aged 45-84 years, without known cardiovascular disease (2000-2002), from the Multi-Ethnic study of Atherosclerosis. Cox-Proportional hazards models were used to examine associations of early, and age at menopause with incident HF. In 2123 post-menopausal women in whom cardiac magnetic resonance imaging was obtained at baseline, we explored associations of early, and age at menopause with LV measures using multivariable linear regression.
Over a median follow-up of 8.5 years, we observed 71 HF events. There were no significant interactions with ethnicity for incident HF (Pinteraction>0.05). In adjusted analysis, early menopause was associated with increased risk of incident HF [1.66 (1.01-2.73)], while each year increase in age at menopause was associated with decreased risk of incident HF [0.96 (0.94-0.99)]. We observed significant interactions between early menopause and ethnicity for LV mass to volume ratio (LVMVR), Pinteraction=0.02. In Chinese-American women, early menopause was associated with higher LVMVR (+0.11, p=0.0002), while each year increase in age at menopause was associated with lower LVMVR (−0.004, p=0.04) at baseline.
An older menopausal age is independently associated with decreased risk of incident HF. Concentric LV remodelling, indicated by a higher LVMVR was present in Chinese-American women with early menopause at baseline.
Menopause; Heart failure; Estrogen
Limitations in mobility are common among older adults with cardiovascular and cardiometabolic disorders and have profound effects on health and well-being. With the growing population of older adults in the United States, effective and scalable public health approaches are needed to address this problem. Our goal was to determine the effects of a physical activity and weight loss intervention on 18-month change in mobility among overweight or obese older adults in poor cardiovascular health.
The study design was a translational, randomized controlled trial of physical activity (PA) and weight loss (WL) on mobility in overweight or obese older adults with cardiovascular disease (CVD) or at risk for CVD. The study was conducted within the community infrastructure of Cooperative Extension Centers. Participants were randomized to 1 of 3 interventions: PA, WL+PA, or a successful aging (SA) education control arm. The primary outcome was time to complete a 400-m walk in seconds (400MWT).
A significant treatment effect (P=.002) and follow-up testing revealed that the WL+PA group improved their 400MWT (adjusted mean [SE], 323.3 [3.7] seconds) compared with both PA (336.3 [3.9] seconds; P=.02) and SA (341.3 [3.9] seconds; P<.001). Participants with poorer mobility at baseline benefited the most (P<.001).
Existing community infrastructures can be effective in delivering lifestyle interventions to enhance mobility in older adults in poor cardiovascular health with deficits in mobility; attention should be given to intervening on both weight and sedentary behavior since weight loss is critical to long-term improvement in mobility.
In a non-clinical trial setting, to determine the proportion of individuals with coronary artery disease (CAD) with optimal risk factor levels based on the Clinical Outcomes Utilizing Revascularization and Aggressive DruG Evaluation (COURAGE) trial.
In COURAGE, the addition of percutaneous coronary intervention (PCI) to optimal medical therapy did not reduce the risk of death or myocardial infarction in stable CAD patients but resulted in more revascularization procedures.
REGARDS is a national prospective cohort study of 30,239 African American and White community-dwelling individuals aged >45 years enrolled in 2003-7. We calculated the proportion of 3,167 participants with self-reported CAD meeting 7 risk factor goals based on COURAGE: 1) aspirin use, 2) systolic blood pressure <130 mmHg and diastolic blood pressure <85 mmHg (<80 mmHg if diabetic), 3) low density lipoprotein cholesterol <85 mg/dL, high density lipoprotein cholesterol >40 mg/dL, and triglycerides <150 mg/dL, 4) fasting glucose <126 mg/dL, 5) nonsmoking status, 6) body mass index <25 kg/m,2 and 7) exercise ≥4 days per week.
The mean age of participants was 69±9 years, 33% were African American, and 35% were female. Overall, the median number of goals met was 4. Less than a quarter met ≥5 of the 7 goals, and 16% met all 3 goals for aspirin, blood pressure, and LDL-C. Older age, white race, higher income, more education, and higher physical functioning were independently associated with meeting more goals.
There is substantial room for improvement in risk factor reduction among US individuals with CAD.
coronary artery disease; prevention; risk factors
Whether measuring and reporting of coronary artery calcium scores (CACS) might lead to changes in cardiovascular risk management is not established. In this observational study we examined whether high baseline CACS were associated with the initiation as well continuation of new lipid lowering medication (LLM), blood pressure lowering medication (BPLM) and regular aspirin (ASA) use in a multi-ethnic population-based cohort.
Methods and Results
MESA is a prospective cohort study of 6814 participants free of clinical cardiovascular disease at entry who underwent CAC testing at baseline examination (exam 1). Information on LLM, BPLM and regular ASA usage was also obtained at baseline, and at exams 2 and 3 (average of 1.6 and 3.2 years after baseline respectively). In this study we examined: 1) initiation of these medications at exam 2 among participants not taking these medications at baseline; and 2) continuation of medication use to exam 3 among participants already on medication at baseline. Among MESA participants, initiation of LLM, BPLM and ASA was greater in those with higher CACS After taking into account age, gender, race, MESA site, LDL cholesterol, diabetes mellitus, BMI, smoking status, hypertension, systolic blood pressure, and SES (income, education and health insurance), the risk ratios for medication initiation comparing those with CACS>400 vs. CACS=0 were 1.53 (95% CI: 1.08, 2.15) for LLM, 1.55 (1.10-- 2.17) for BPLM, and 1.32 (1.03–1.69) for ASA initiation, respectively. The risk ratios for medication continuation among those with CAC>400 vs. CACS=0 were 1.10 (95% CI: 1.01–1.20) for LLM, 1.05 (1.02–1.08) for BPLM, and 1.14 (1.04- 1.25) for ASA initiation, respectively.
CACS>400 was associated with a higher likelihood of initiation and continuation of LLM, BPLM and ASA. The association was weaker for continuation than for initiation of these preventive therapies.
Coronary artery calcification; Computed tomography; Medications; Adherence; Prevention
The American College of Cardiology/American Heart Association Pooled Cohort risk equations were developed to estimate atherosclerotic cardiovascular disease (ASCVD) risk and guide statin initiation.
Assess calibration and discrimination of the Pooled Cohort risk equations in a contemporary US population.
Design, Setting, and Participants
Adults 45-79 years enrolled in the REasons for Geographic And Racial Differences in Stroke study between January 2003 and October 2007 and followed through December 2010. We studied participants for whom ASCVD risk may trigger a discussion of statin initiation (those without clinical ASCVD or diabetes, LDL-C between 70-189 mg/dL, not taking statins; n=10,997).
Main Outcomes and Measures
Predicted risk and observed adjudicated ASCVD incidence (non-fatal myocardial infarction, coronary heart disease [CHD] death, non-fatal or fatal stroke) at 5 years as REGARDS participants have not been followed 10 years. Additional analyses, limited to Medicare beneficiaries (n=3,333), added ASCVD events identified in claims data.
There were 338 adjudicated events (192 CHD events, 146 strokes). The observed and predicted 5-year ASCVD incidence per 1,000 person-years for participants with 10-year predicted ASCVD risk <5% was 1.9 (95%CI: 1.3 – 2.7) and 1.9, risk 5% to <7.5% was 4.8 (95%CI: 3.4 – 6.7) and 4.8, risk 7.5% to <10% was 6.1 (95%CI: 4.4 – 8.6) and 6.9, and risk ≥10% was 12.0 (95%CI: 10.6 – 13.6) and 15.1 (Hosmer-Lemeshow χ2 19.9 p-value=0.01). The c-index was 0.72 (95%CI: 0.70–0.75). There were 234 ASCVD events (120 CHD events, 114 strokes) among Medicare-linked participants and the observed and predicted 5-year ASCVD incidence per 1,000 person-years for participants with predicted risk <7.5% was 5.3 (95% CI: 2.8 – 10.1) and 4.0, risk 7.5% to <10% was 7.9 (95% CI: 4.6 – 13.5) and 6.4, and risk ≥10% was 17.4 (95% CI: 15.3–19.8) and 16.4 (Hosmer-Lemeshow χ2 5.4 p-value=0.71). The c-index was 0.67 (95%CI: 0.64 – 0.71)
Conclusions and Relevance
In this cohort of US adults for whom statin initiation is considered based on the ACC/AHA Pooled Cohort risk equations, observed and predicted 5-year ASCVD risks were similar, indicating that these risk equations were well calibrated in the population for which they were designed to be used.
Framingham risk score (FRS) underestimates risk in young adults. LV mass (LVM) relates to cardiovascular disease (CVD), with unclear value in youth. In a young biracial cohort, we investigate how FRS predicts CVD over 20 years and the incremental value of LVM. We also explore the predictive ability of different cut-points for hypertrophy.
We assessed FRS and echocardiography-derived LVM (indexed by BSA or height2.7) from 3980 African-American and white CARDIA participants (1990-1991); and followed over 20 years for a combined endpoint: cardiovascular death; nonfatal myocardial infarction, heart failure, cerebrovascular disease, and peripheral artery disease. We assessed the predictive ability of FRS for CVD and also calibration, discrimination, and net reclassification improvement for adding LVM to FRS.
Mean age was 30±4 years, 46% males, and 52% white. Event incidence (n = 118) across FRS groups was, respectively, 1.3%, 5.4%, and 23.1% (p<0.001); and was 1.4%, 1.3%, 3.7%, and 5.4% (p<0.001) across quartiles of LVM (cut-points 117g, 144g, and 176g). LVM predicted CVD independently of FRS, with the best performance in normal weight participants. Adding LVM to FRS modestly increased discrimination and had a statistically significant reclassification. The 85th percentile (≥116 g/m2 for men; ≥96 g/m2 for women) showed event prediction more robust than currently recommended cut-points for hypertrophy.
In a biracial cohort of young adults, FRS and LVM are helpful independent predictors of CVD. LVM can modestly improve discrimination and reclassify participants beyond FRS. Currently recommended cut-points for hypertrophy may be too high for young adults.
young adults; cardiovascular risk; left ventricular hypertrophy; echocardiography
The aim of the present study was to determine whether serum urate (sUA) concentration is positively associated with subclinical atherosclerosis, independent of body mass index (BMI), among generally healthy adults.
Design and setting
The CARDIA study followed 5115 black and white individuals aged 18–30 years in 1985–1986 (year 0). Subclinical atherosclerosis comprised coronary artery calcified plaque (CAC; years 15, 20 and 25) and maximum common carotid intima–media thickness (IMT; year 20). sUA (years 0, 10, 15 and 20) was modelled as gender-specific quartiles that were pooled. Discrete-time hazard regressions and generalized linear regressions were used for analyses.
Mean sUA concentration was lower in women than in men, and increased with age. Adjusting for demographic and lifestyle factors, the highest versus lowest quartile of sUA at year 0 was associated with a 44% [95% confidence interval (CI) 20%, 73%] greater risk of CAC progression from year 15 to 25 (Ptrend < 0.001), which was attenuated by adjustment for BMI at year 0 (Ptrend = 0.45). A stronger association was found between sUA at year 15 and CAC progression at year 20 or 25 (hazard ratio 2.07, 95% CI 1.66, 2.58 for the highest versus lowest sUA quartile Ptrend < 0.001), which was attenuated but remained significant with additional adjustment for BMI at year 15 (Ptrend = 0.01). A greater increment in sUA concentration from year 0 to year 15, independent of change in BMI, was related to a higher risk of CAC progression (Ptrend < 0.001). Similar associations were found between sUA and IMT, but only in men.
sUA may be an early biomarker for subclinical atherosclerosis in young adults; starting in early middle age, sUA predicts subclinical atherosclerosis independently of BMI.
calcified plaque; intima–media thickness; subclinical atherosclerosis; urate; uric acid
Despite the benefits of regular physical activity among older adults, physical activity rates are low in this population. The Program for Active Aging and Community Engagement (PACE) is an ongoing randomized controlled trial designed to compare the effects of two interventions on physical activity at 12 months among older adults. A total of 300 men and women aged 55 years or older will be randomized into either a healthy aging (HA) control intervention (n = 150), which is largely based upon educational sessions, or a prosocial behavior physical activity (PBPA) intervention (n = 150), which incorporates structured physical activity sessions, cognitive-behavioral counseling, and opportunities to earn food for donation to a regional food bank based on weekly physical activity and volunteering. The PBPA intervention is delivered at a local YMCA, and a regional grocery store chain donates the food to the food bank. Data will be collected at baseline, 3, 6, and 12 months. The primary outcome is physical activity as assessed by the Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire at 12 months. Secondary outcomes include physical function and health-related quality of life. If successful, the PACE study will demonstrate that prosocial behavior and volunteerism may be efficaciously incorporated into interventions and will provide evidence for a novel motivating factor for physical activity.
Randomized controlled trial; Older adults; Physical activity; Prosocial behavior; Community partnership
The purpose of this study was to identify determinants of 20 year change in left ventricular (LV) mass (LVM) and LV geometry in black and white young adults in the CARDIA Study.
Methods and Results
We studied 2426 black and white men and women (54.7% Caucasian) aged 43-55 years with cardiovascular (CV) risk factor data and echocardiograms from CARDIA year 5 and 25 examinations. In regression models, year 25 LVM or relative wall thickness was the dependent variable and with year 5 echo values, age, gender, race, body mass index (BMI), change in BMI, mean arterial blood pressure, change in mean blood pressure, heart rate (HR), change in HR, tobacco use, presence of diabetes, alcohol use, and physical activity score as independent variables. LVM and relative wall thickness increased while prevalence of normal geometry declined from 84.2% to 69.7%. Significant determinants of year 25 LVM/m2.7 were year 5 LVM, year 5 and change in BMI, year 5 and change in mean arterial pressure, year 5 and change in HR, baseline diabetes, and year 5 tobacco and/or alcohol use (overall r2 = 0.40). Significant determinants of year 25 relative LV wall thickness were year 5 value, black race, change in BMI, year 5 and change in mean arterial pressure, starting smoking, and year 5 diabetes. (overall r2 = 0.11).
Prevalence of abnormal LV hypertrophy and geometry increased from young adulthood to middle age. Both young adult CV risk traits and change in these traits predicted change in LV mass/geometry.
echocardiography; left ventricular mass; blood pressure; obesity; risk assessment
Risk markers including coronary artery calcium (CAC), carotid intima-media thickness (CIMT), ankle-brachial Index (ABI), brachial flow-mediated dilation (FMD), high sensitivity C -reactive protein (hs-CRP) and family history (FH) of coronary heart disease (CHD) have been reported to improve on the Framingham risk score (FRS) for prediction of CHD. However, there are no direct comparisons of these markers for risk prediction in a single cohort.
We compared improvement in prediction of incident CHD/cardiovascular disease (CVD) of these 6 risk markers within intermediate risk participants (5 % < FRS < 20%) in the Multi-Ethnic Study of Atherosclerosis (MESA).
Design, Setting and Participants
Of 6814 MESA participants from 6 US field centers, 1330 were intermediate risk, without diabetes mellitus, and had complete data on all 6 markers. Recruitment spanned July 2000 to September 2002; follow-up extended through May 2011. Probability- weighted Cox proportional hazard models were used to estimate hazard ratios (HR). Area under the receiver operator characteristic curve (AUC) and net reclassification improvement (NRI) were used to compare incremental contributions of each marker when added to the FRS + race/ethnicity.
Main Outcome Measures
Incident CHD defined as MI, angina followed by revascularization, resuscitated cardiac arrest or CHD death. Incident CVD additionally included stroke or CVD death.
After median follow-up of 7.6 years (IQR 7.3 – 7.8 years), 94 CHD and 123 CVD events occurred. CAC, ABI, hs-CRP and FH were independently associated with incident CHD in multivariable analyses [HR (95%CI: 2.60(1.94-3.50), 0.79(0.66-0.95), 1.28(1.00-1.64) and 2.18(1.38-3.42) respectively]. CIMT and FMD were not associated with incident CHD in multivariable analyses [HR (95%CI) 1.17(0.95- 1.45) and 0.95(0.78 −1.14) respectively]. Although the addition of the markers individually to the FRS +race/ethnicity improved the AUC, CAC afforded the highest increment (0.623 vs. 0.784) while FMD afforded the least [0.623 vs. 0.639]. For incident CHD, the NRI with CAC was 0.659, FMD 0.024, ABI 0.036, CIMT 0.102, FH 0.160 and hs-CRP 0.079. Similar results were obtained for incident CVD.
CAC, ABI, hs-CRP and FH are independent predictors of incident CHD/CVD in intermediate risk individuals. CAC provides superior discrimination and risk reclassification compared with other risk markers.
Single measures of blood pressure (BP) levels are associated with the development of atherosclerosis; however, long-term patterns in BP and their impact on CVD risk are poorly characterized.
To identify common BP trajectories throughout early adulthood and to determine their association with presence of coronary artery calcification (CAC) during middle age.
We used data from the CARDIA study from baseline in 1985-1986 through 25 years of follow-up (2010-2011).
Prospective cohort study
CARDIA participants were Black and White men and women aged 18-30 years at baseline.
We examined systolic BP, diastolic BP, and mid-BP [calculated as (SBP+DBP)/2 and an important marker of CHD risk among younger populations] at baseline and years 2, 5, 7, 10, 15, 20, and 25. Latent mixture modeling was used to identify trajectories in SBP, DBP and mid-BP over time.
Main Outcome Measure
Coronary artery calcification greater than or equal to Agatston score of 100 Agatston units at year 25.
Among 4,681 participants, we identified 5 distinct mid-BP trajectories: Low-Stable (22% [95% CI 19.9-23.7], n=987), Moderate-Stable (42% [40.3-44.3], n=2,085), Moderate-Increasing (12% [10.4-14.0], n=489), Elevated-Stable (19% [17.1-20.0], n=903) and Elevated-Increasing (5% [4.0-5.5], n=217). As compared to the Low-Stable group, trajectories with elevated BP levels had greater odds of having CAC >100. Adjusted odds ratios (95% CI) were 1.44 (0.83-2.49) for Moderate-Stable, 1.86 (0.91-3.82) for Moderate-Increasing, 2.28 (1.24-3.70) for Elevated-Stable, and 3.70 (1.66-8.20) for Elevated-Increasing groups. The adjusted prevalence of CAC ≥ 100 was 5.8% in the Low-Stable group. These ORs represent an absolute increase of 2.7%, 5%, 6.3% and 12.9% for the prevalence of CAC ≥100 for the Moderate-Stable, Moderate-Increasing, Elevated Stable and Elevated Increasing groups respectively as compared to the Low-Stable Group. Associations were not altered after adjustment for baseline and year 25 BP. Findings were similar for trajectories of isolated systolic BP trajectories, but were attenuated for diastolic BP trajectories.
Conclusions and Relevance
BP trajectories throughout young adulthood vary and higher BP trajectories were associated with an increased risk of CAC in middle age. Long-term trajectories in BP may assist in more accurate identification of individuals with subclinical atherosclerosis.
blood pressure; calcium; epidemiology; risk factors
The amount of cholesterol per LDL particle is variable and related in part to particle size, with smaller particles carrying less cholesterol. This variability causes concentrations of LDL cholesterol (LDL-C) and LDL particles (LDL-P) to be discordant in many individuals.
LDL-P measured by nuclear magnetic resonance (NMR) spectroscopy, calculated LDL-C, and carotid intima-media thickness (IMT) were assessed at baseline in the Multi-Ethnic Study of Atherosclerosis (MESA), a community-based cohort of 6814 persons free of clinical CVD at entry and followed for CVD events (n=319 during 5.5-year follow-up). Discordance, defined as values of LDL-P and LDL-C differing by ≥ 12 percentile units to give equal-sized concordant and discordant subgroups, was related to CVD events and to carotid IMT in models predicting outcomes for a 1 SD difference in LDL-C or LDL-P, adjusted for age, sex and race.
LDL-C and LDL-P were associated with incident CVD overall: hazard ratios (HR [95% CI]) 1.20 [1.08, 1.34] and 1.32 [1.19, 1.47], respectively, but for those with discordant levels, only LDL-P was associated with incident CVD (HR: 1.45 [1.19, 1.78]) (LDL-C HR: 1.07 [0.88, 1.30])). IMT also tracked with LDL-P rather than LDL-C, i.e., adjusted mean IMT of 958, 932, and 917 μm in the LDL-P > LDL-C discordant, concordant, and LDL-P < LDL-C discordant subgroups, respectively, with the difference persisting after adjustment for LDL-C (p=0.002) but not LDL-P (p=0.60).
For individuals with discordant LDL-C and LDL-P levels, the LDL-attributable atherosclerotic risk is better indicated by LDL-P.
LDL particle number; LDL cholesterol; cardiovascular disease risk; NMR; lipoproteins
Dyslipidemia is a known risk factor for coronary disease, but its role in heart failure (HF) development is less well-defined.
Methods and Results
We included 5688 participants, aged 45 to 84 years, without clinical cardiovascular disease, and not receiving lipid-lowering medications at baseline, from the Multiethnic Study of Atherosclerosis. Cox-proportional hazards models were used to evaluate associations of triglyceride, total cholesterol/high-density lipoprotein–cholesterol (HDL-C) ratio, HDL-C, and non HDL-C with incident HF. We investigated for effect-modification by diabetes mellitus status and sex. During a median follow-up of 8.5 years, there were 152 incident HF cases. There were no interactions by sex. We observed significant interactions between triglyceride and diabetes mellitus (Pinteraction<0.05). We stratified our analyses by diabetes mellitus status. In participants with diabetes, the hazard ratios were 2.03 (0.97–4.27) and 1.68 (1.18–2.38) for high triglyceride and log of triglyceride, respectively, after adjusting for confounders, comorbidities, and diabetes mellitus severity/treatment. The association of high triglyceride with incident HF was attenuated by interim myocardial infarction. The hazard ratios were greatest in participants with diabetes who also had high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio (3.59 [2.03–6.33], 3.62 [2.06–6.36], and 3.54 [1.87–6.70], respectively). Lipid measures were not associated with incident HF in individuals without diabetes.
The risk of incident HF is greater in individuals with diabetes mellitus who also have high triglyceride, low HDL-C, or high total cholesterol/HDL-C ratio. The association of high triglyceride with incident HF is partly mediated by myocardial infarction.
diabetes mellitus; heart failure; lipids
Specific constellations of lipoprotein particle features, reflected as differences in mean lipoprotein particle diameters, are associated with risk of insulin resistance (IR) and cardiovascular disease (CVD). The associations of lipid profiles with disease risk differ by race/ethnicity, the reason for this is not clear. We aimed to examine whether there were additional genetic differences between racial / ethnic groups on lipoprotein profile.
Methods and results
Genotypes were assessed using the Affymetrix 6.0 array in 817 related Caucasian participants of the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN). Association analysis was conducted on fasting mean particle diameters using linear models, adjusted for age, sex and study center as fixed effects, and pedigree as a random effect. Replication of associations reaching P<1.97 * 10−05 (the level at which we achieved at least 80% power to replicate SNP-phenotype associations) was conducted in the Caucasian population of the Multi-Ethnic Study of Atherosclerosis (MESA; N=2430). Variants which replicated across both Caucasian populations were subsequently tested for association in the African-American (N=1594), Chinese (N=758) and Hispanic (N=1422) populations of MESA. Variants in the APOB gene region were significantly associated with mean VLDL diameter in GOLDN, and in the Caucasian and Hispanic populations of MESA, while variation in the hepatic lipase (LIPC) gene was associated with mean HDL diameter in both Caucasians populations only.
Our findings suggest the genetic underpinnings of mean lipoprotein diameter differ by race/ethnicity. As lipoprotein diameters are modifiable, this may lead new strategies to modify lipoprotein profiles during the reduction of IR that are sensitive to race / ethnicity.
Lipoprotein size; race / ethnicity; ApoB; Hepatic Lipase; NMR
Since the Diabetes Prevention Project (DPP) demonstrated that lifestyle weight-loss interventions can reduce the incidence of diabetes by 58%, several studies have translated the DPP methods to public health–friendly contexts. Although these studies have demonstrated short-term effects, no study to date has examined the impact of a translated DPP intervention on blood glucose and adiposity beyond 12 months of follow-up.
To examine the impact of a 24-month, community-based diabetes prevention program on fasting blood glucose, insulin, insulin resistance as well as body weight, waist circumference, and BMI in the second year of follow-up.
An RCT comparing a 24-month lifestyle weight-loss program (LWL) to an enhanced usual care condition (UCC) in participants with prediabetes (fasting blood glucose=95–125 mg/dL). Data were collected in 2007–2011; analyses were conducted in 2011–2012.
301 participants with prediabetes were randomized; 261 completed the study. The intervention was held in community-based sites.
The LWL program was led by community health workers and sought to induce 7% weight loss at 6 months that would be maintained over time through decreased caloric intake and increased physical activity. The UCC received two visits with a registered dietitian and a monthly newsletter.
Main outcome measures
The main measures were fasting blood glucose, insulin, insulin resistance, body weight, waist circumference, and BMI.
Intent-to-treat analyses of between-group differences in the average of 18- and 24-month measures of outcomes (controlling for baseline values) revealed that the LWL participants experienced greater decreases in fasting glucose (−4.35 mg/dL); insulin (−3.01 μU/ml); insulin resistance (−0.97); body weight (−4.19 kg); waist circumference (−3.23 cm); and BMI (−1.40), all p-values <0.01.
A diabetes prevention program administered through an existing community-based system and delivered by community health workers is effective at inducing significant long-term reductions in metabolic indicators and adiposity.
This study is registered at Clinicaltrials.gov NCT00631345.
Although numerous studies have translated the Diabetes Prevention Program lifestyle intervention into various settings, no study to date has reported a formal cost analysis.
To describe costs associated with the Healthy Living Partnerships to Prevent Diabetes (HELP PD) trial.
HELP PD was a 24-month RCT testing the impact of a lifestyle weight-loss intervention administered through a diabetes education program and delivered by community health workers (CHWs) on blood glucose and body weight among prediabetics.
In all, 301 participants with prediabetes were randomized in Forsyth County NC. Data reported in these analyses were collected in 2007–2011 and analyzed in 2011–2012.
The lifestyle weight-loss group had a 7% weight loss goal achieved and maintained by caloric restriction and increased physical activity. The usual care group received two visits with a registered dietitian and monthly newsletters.
Main outcome measures
Measures are direct medical costs, direct nonmedical costs and indirect costs over the 2-year study period. Research costs are excluded.
The direct medical cost (in 2010 dollars) to identify one participant was $16.85. Direct medical costs per capita for participants in the usual care group were $142 and $850 for lifestyle weight-loss participants. Per capita direct costs of care outside the study were $7454 for the usual care group and $5177 for the lifestyle weight-loss group. Per capita direct nonmedical costs were $12,881 for the usual care group and $13,836 for the lifestyle weight-loss group. The lifestyle weight-loss group in HELP PD cost $850 in direct medical costs for 2 years, compared to $2631 in direct medical costs for the first 2 years of DPP.
A community-based translation of the DPP can be delivered effectively and with reduced costs.
Prior studies demonstrating shorter length of stay (LOS) from coronary computed tomography angiography (CCTA) relative to stress testing in emergency department (ED) patients have not considered time of patient presentation. The objectives of this study were to determine whether low-risk chest pain patients receiving stress testing or CCTA have differences in ED plus observation unit (OU) LOS, and if there are disparities in testing modality use, based upon the time of patient presentation to the ED.
The authors examined a cohort of low-risk chest pain patients evaluated in an ED-based OU using prospective and retrospective OU registry data. During the study period, stress testing and CCTA were both available from 08:00 to 17:00 hrs. CCTA was not available on weekends, and therefore only subjects presenting on weekdays were included. Cox regression analysis was used to model the effect of testing modality (stress testing vs. CCTA) on OU LOS. Separate models were fit based on time of patient presentation to the ED using four hour blocks beginning at midnight. The primary independent variable was testing modality: stress testing or CCTA. Age, sex, and race were included as covariates. Logistic regression was used to model testing modality choice by time period adjusted for age, sex, and race.
Over the study period, 841 subjects presented Monday through Friday. Median LOS was 18.0 hours (IQR 11.7 to 22.9 hours). Objective cardiac testing was completed in 788 of 841 (94%) patients, with 496 (63%) receiving stress testing and 292 (37%) receiving CCTA. After adjusting for age, race, and sex, patients presenting between 08:00 and 11:59 hrs not only had a shorter LOS associated with CCTA (p < 0.0001), but also had a greater likelihood of being tested by CCTA (p = 0.001). None of the other time periods had significant differences in LOS or testing modality choice for CCTA relative to stress testing.
In an OU setting with weekday and standard business hours CCTA availability, CCTA testing was associated with shorter LOS among low-risk chest pain patients only in patients presenting to the ED between 08:00 and 11:59 hrs. That time period was also associated with a greater likelihood of being tested by CCTA, suggesting that ED providers may have intuited the inability of CCTA to shorten LOS during other times.
To evaluate the strength of association of body mass index (BMI) and waist circumference (WC) with incident heart failure (HF), exploring our associations by ethnicity and age.
Design and Methods
We included 6,809 participants, aged 45–84 years, without clinical cardiovascular disease (2000–2002), from the Multi-Ethnic Study of Atherosclerosis. Cox-Proportional hazards models were used to examine associations of BMI and WC with incident HF. The predictive abilities of BMI and WC were compared using receiver operating characteristic curves.
Over a median follow-up of 7.6 years, there were 176 cases. BMI and WC were associated with incident HF in men [1.33 (1.10–1.61) and 1.38 (1.18–1.62) respectively] and women [1.70 (1.33–2.17) and 1.64 (1.29–2.08) respectively]. These associations became non-significant after adjusting for obesity-related conditions (hypertension, dysglycemia, hypercholesterolemia, left ventricular hypertrophy, kidney disease and inflammation). The associations of BMI and WC did not vary significantly by ethnicity or age-group, but were inverse in Hispanic men. The area under the curve for BMI and WC was 0.749 and 0.750, respectively, in men and 0.782 and 0.777, respectively, in women.
The association between obesity and incident HF is largely mediated by obesity-related conditions. BMI and WC have similar predictive abilities for incident HF.
Obesity; heart failure; body mass index and waist circumference
Recent obesity prevention initiatives focus on healthy neighborhood design, but most research examines neighborhood food retail and physical activity (PA) environments in isolation. We estimated joint, interactive, and cumulative impacts of neighborhood food retail and PA environment characteristics on body mass index (BMI) throughout early adulthood.
Methods and Findings
We used cohort data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study [n=4,092; Year 7 (24-42 years, 1992-1993) followed over 5 exams through Year 25 (2010-2011); 12,921 person-exam observations], with linked time-varying geographic information system-derived neighborhood environment measures. Using regression with fixed effects for individuals, we modeled time-lagged BMI as a function of food and PA resource density (counts per population) and neighborhood development intensity (a composite density score). We controlled for neighborhood poverty, individual-level sociodemographics, and BMI in the prior exam; and included significant interactions between neighborhood measures and by sex. Using model coefficients, we simulated BMI reductions in response to single and combined neighborhood improvements. Simulated increase in supermarket density (from 25th to 75th percentile) predicted inter-exam reduction in BMI of 0.09 kg/m2 [estimate (95% CI): -0.09 (-0.16, -0.02)]. Increasing commercial PA facility density predicted BMI reductions up to 0.22 kg/m2 in men, with variation across other neighborhood features [estimate (95% CI) range: -0.14 (-0.29, 0.01) to -0.22 (-0.37, -0.08)]. Simultaneous increases in supermarket and commercial PA facility density predicted inter-exam BMI reductions up to 0.31 kg/m2 in men [estimate (95% CI) range: -0.23 (-0.39, -0.06) to -0.31 (-0.47, -0.15)] but not women. Reduced fast food restaurant and convenience store density and increased public PA facility density and neighborhood development intensity did not predict reductions in BMI.
Findings suggest that improvements in neighborhood food retail or PA environments may accumulate to reduce BMI, but some neighborhood changes may be less beneficial to women.
Poor prognosis in heart failure (HF) patients with diabetes is often attributed to increased co‐morbidity and advanced disease. Further, this effect may be worse in women.
To determine whether the effect of diabetes on outcomes and the sex‐related variation persisted in a propensity score‐matched HF population, and whether the sex‐related variation was a function of age.
Of the 7788 HF patients in the Digitalis Investigation Group trial, 2218 had a history of diabetes. Propensity score for diabetes was calculated for each patient using a non‐parsimonious logistic regression model incorporating all measured baseline covariates, and was used to match 2056 (93%) diabetic patients with 2056 non‐diabetic patients.
All‐cause mortality occurred in 135 (25%) and 216 (39%) women without and with diabetes (adjusted HR = 1.67; 95% CI = 1.34 to 2.08; p<0.001). Among men, 535 (36%) and 609 (41%) patients without and with diabetes died from all causes (adjusted HR = 1.21; 95% CI = 1.07 to 1.36; p = 0.002). Sex–diabetes interaction (overall adjusted p<0.001) was only significant in patients ⩾65 years (15% absolute risk increase in women; multivariable p for interaction = 0.005), but not in younger patients (2% increase in women; p for interaction = 0.173). Risk‐adjusted HR (95% CI) for all‐cause hospitalisation for women and men were 1.49 (1.28 to 1.72) and 1.21 (1.11 to 1.32), respectively, also with significant sex–diabetes interaction (p = 0.011).
Diabetes‐associated increases in morbidity and mortality in chronic HF were more pronounced in women, and theses sex‐related differences in outcomes were primarily observed in elderly patients.
Numerous studies have translated the Diabetes Prevention Program (DPP) for community-based settings, and the results are encouraging. This commentary discusses one community-based DPP translational study, Healthy Living Partnerships to Prevent Diabetes, in detail, as well as the implications of DPP translational studies for public policy.
Health care access is associated with improved control of multiple chronic diseases, but the association between health care access and weight change is unclear. This study aims to test the association between health care access and weight change.
The Coronary Artery Risk Development in Young Adults (CARDIA) study is a multi-center population-based prospective study. Weight change was calculated at 3 and 13 years after CARDIA year 7 (1992–1993). Health care access was defined as no barriers or one or more barriers to access (health insurance gap, no usual source of care, not seeking care due to expense). Intermediary variables evaluated included history of dieting, and use of diet pills, meal replacements, or weight control programs.
Four cities in the United States.
Participants were aged 18–30 years at baseline (1985–1986). Analyses include 3922 black and white men and women with relevant data from CARDIA years 7, 10, and 20 (1992–1993, 1995–1996, and 2005–2006, respectively).
Mean weight change was +4.9 pounds by 3 years and +18.7 pounds by 13 years, with no differences by health care access. Being on a weight-reducing diet was not consistently associated with health care access across examinations. Use of diet pills, meal replacements or organized weight control programs was low, and did not vary by health care access.
Weight gain was high irrespective of health care access. Public health and clinical approaches are needed to address weight gain.
health care accessibility; body weight change
Physical inactivity contributes to metabolic syndrome (MetS) in overweight/obesity. However, little is known about this relationship in prediabetes.
The study purpose is to examine relationships between physical activity (PA) and MetS in prediabetes. The Healthy Living Partnerships to Prevent Diabetes tested a community translation of the Diabetes Prevention Program (DPP). Three hundred one overweight/obese prediabetics provided walking minutes/week (WM) and total activity minutes/week (AM) via the International Physical Activity Questionnaire. MetS was at least 3 of waist (men ≥ 102 cm, women ≥ 88 cm), triglycerides (≥150 mg·dl), blood pressure (≥130·85 mm Hg), glucose (≥100mg·dl), and HDL (men < 40mg·dl, women < 50mg·dl).
The sample was 57.5% female, 26.7% nonwhite/Hispanic, 57.9 ± 9.5 years and had a body mass index (BMI) 32.7 ± 4 kg·m2. Sixty percent had MetS. Eighteen percent with MetS reported at least 150 AM compared with 29.8% of those without MetS. The odds of MetS was lower with greater AM (Ptrend = .041) and WM (Ptrend = .024). Odds of MetS with 0 WM were 2.08 (P = .046) and with no AM were 2.78 (P = .009) times those meeting goal. One hour additional WM led to 15 times lower MetS odds.
Meeting PA goals reduced MetS odds in this sample, which supported PA for prediabetes to prevent MetS.
obesity; walking; physical activity