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1.  Association Between Retinopathy and Cardiovascular Disease in Patients with Chronic Kidney Disease (From the Chronic Renal Insufficiency Cohort [CRIC] Study) 
The American Journal of Cardiology  2012;110(2):246-253.
Patients with chronic kidney disease (CKD) experience co-morbid illneses including cardiovascular disease (CVD) and retinopathy. The purpose of this study was to assess the association between retinopathy and self reported CVD in a subgroup of the participants of the Chronic Renal Insufficiency Cohort (CRIC) study. In this observational, ancillary investigation, 2605 CRIC participants were invited to participate in this study, and non-mydriatic fundus photographs in both eyes were obtained in 1936 subjects. Photographs were reviewed in a masked fashion at a central photograph reading center. Presence and severity of retinopathy (diabetic, hypertensive or other) and vessel diameter caliber were assessed using standard protocols by trained graders masked to information about study participants. History of self-reported cardiovascular disease was obtained using a medical history questionnaire. Kidney function measurements, traditional and non-traditional risk factors for CVD were obtained from the CRIC study. Greater severity of retinopathy was associated with higher prevalence of any cardiovascular disease and this association persisted after adjustment for traditional risk factors for CVD. Presence of vascular abnormalities usually associated with hypertension was also associated with increased prevalence of CVD. We found a direct relationship between CVD prevalence and mean venular caliber. In conclusion, presence of retinopathy was associated with CVD, suggesting that retinovascular pathology may be indicative of macrovascular disease even after adjustment for renal dysfunction and traditional CVD risk factors. This would make assessment of retinal morphology a valuable tool in chronic kidney disease studies of CVD outcomes.
PMCID: PMC3383900  PMID: 22516527
Retinopathy; chronic kidney disease; cardiovascular disease
2.  CKD in Hispanics: Baseline Characteristics From the CRIC (Chronic Renal Insufficiency Cohort) and Hispanic-CRIC Studies 
Little is known regarding chronic kidney disease (CKD) in Hispanics. We compared baseline characteristics of Hispanic participants in the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC (H-CRIC) Studies with non-Hispanic CRIC participants.
Study Design
Cross-sectional analysis
Setting and Participants
Participants were aged 21–74 years with CKD using age-based glomerular filtration rate (eGFR) at enrollment into the CRIC/H-CRIC Studies. H-CRIC included Hispanics recruited at the University of Illinois from 2005–2008 while CRIC included Hispanics and non-Hispanics recruited at seven clinical centers from 2003–2007.
Blood pressure, angiotensin-converting enzyme (ACE) inhibitor/angiotensin receptor blocker (ARB) use, CKD-associated complications
Demographic characteristics, laboratory data, blood pressure, and medications were assessed using standard techniques and protocols
Among H-CRIC/ CRIC participants, 497 were Hispanic, 1650 non-Hispanic Black, and 1638 non-Hispanic White. Low income and educational attainment were nearly twice as prevalent in Hispanics compared with non-Hispanics (p<0.01). Hispanics had self-reported diabetes (67%) more frequently than non-Hispanic Blacks (51%) and Whites (40%) (p<0.01). Blood pressure > 130/80 mmHg was more common in Hispanics (62%) compared with Blacks (57%) and Whites (35%) (p<0.05), and abnormalities in hematologic, metabolic, and bone metabolism parameters were more prevalent in Hispanics (p<0.05), even after stratifying by entry eGFR. Hispanics had the lowest receipt of ACE inhibitor/ARB among high-risk subgroups, including participants with diabetes, proteinuria, and blood pressure > 130/80 mmHg. Mean eGFR (ml/min/m2) was lower in Hispanics (39.6) than in Blacks (43.7) and Whites (46.2), while median proteinuria was higher in Hispanics (0.72 g/d) than in Blacks (0.24 g/d) and Whites (0.12 g/d) (p<0.01).
Generalizability; observed associations limited by residual bias and confounding
Hispanics with CKD in CRIC/H-CRIC Studies are disproportionately burdened with lower socioeconomic status, more frequent diabetes mellitus, less ACE inhibitor/ARB use, worse blood pressure control, and more severe CKD and associated complications than their non-Hispanic counterparts.
PMCID: PMC3577064  PMID: 21705121
chronic kidney disease; Hispanics; epidemiology
3.  Higher plasma CXCL12 levels predict incident myocardial infarction and death in chronic kidney disease: findings from the Chronic Renal Insufficiency Cohort study 
European Heart Journal  2013;35(31):2115-2122.
Genome-wide association studies revealed an association between a locus at 10q11, downstream from CXCL12, and myocardial infarction (MI). However, the relationship among plasma CXCL12, cardiovascular disease (CVD) risk factors, incident MI, and death is unknown.
Methods and results
We analysed study-entry plasma CXCL12 levels in 3687 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study, a prospective study of cardiovascular and kidney outcomes in chronic kidney disease (CKD) patients. Mean follow-up was 6 years for incident MI or death. Plasma CXCL12 levels were positively associated with several cardiovascular risk factors (age, hypertension, diabetes, hypercholesterolaemia), lower estimated glomerular filtration rate (eGFR), and higher inflammatory cytokine levels (P < 0.05). In fully adjusted models, higher study-entry CXCL12 was associated with increased odds of prevalent CVD (OR 1.23; 95% confidence interval 1.14, 1.33, P < 0.001) for one standard deviation (SD) increase in CXCL12. Similarly, one SD higher CXCL12 increased the hazard of incident MI (1.26; 1.09,1.45, P < 0.001), death (1.20; 1.09,1.33, P < 0.001), and combined MI/death (1.23; 1.13–1.34, P < 0.001) adjusting for demographic factors, known CVD risk factors, and inflammatory markers and remained significant for MI (1.19; 1.03,1.39, P = 0.01) and the combined MI/death (1.13; 1.03,1.24, P = 0.01) after further controlling for eGFR and urinary albumin:creatinine ratio.
In CKD, higher plasma CXCL12 was associated with CVD risk factors and prevalent CVD as well as the hazard of incident MI and death. Further studies are required to establish if plasma CXCL12 reflect causal actions at the vessel wall and is a tool for genomic and therapeutic trials.
PMCID: PMC4132636  PMID: 24306482
Atherosclerosis; Chemokines; Myocardial infarction; CXCL12
4.  Carotid Plaque, Carotid Intima-Media Thickness, and Coronary Calcification Equally Discriminate Prevalent Cardiovascular Disease in Kidney Disease 
American journal of nephrology  2012;36(4):342-347.
Despite the significant morbidity and mortality attributable to cardiovascular disease (CVD), risk stratification remains an important challenge in the chronic kidney disease(CKD) population. We examined the discriminative ability of non-invasive measures of atherosclerosis, including carotid intima-media thickness(cIMT), carotid plaque, coronary artery calcification(CAC) and ascending and descending thoracic aorta calcification(TCAC), and Framingham Risk Score (FRS) to predict self-reported prevalent CVD.
Methods and Results
Participants were enrolled in the cIMT ancillary study of the Chronic Renal Insufficiency Cohort(CRIC) Study and also had all of the above measures within an 18 month period. CVD was present in 21% of study participants. C-statistics were used to ascertain the discriminatory power of each measure of atherosclerosis. The study population (n=220) was 64% male; 51% black and 45% white. The proportion of individuals with estimated glomerular filtration rate ≥60, 45–59, 30–44, and <30ml/min/1.73m2 was 21%, 41%, 28%, and 11%, respectively. In multivariable analyses adjusting for demographic factors, we failed to find a difference between CAC, carotid plaque, and cIMT as predictors of self-reported prevalent CVD (c-statistic 0.70, 95% confidence interval [CI]: 0.62–0.78; c-statistic 0.68, 95% CI: 0.60–0.75, and c-statistic 0.64, CI: 0.56–0.72, respectively). CAC was statistically better than FRS. FRS was the weakest discriminator of self-reported prevalent CVD (c-statistic 0.58).
There was a significant burden of atherosclerosis among individuals with CKD, ascertained by several different imaging modalities. We were unable to find a difference in the ability of CAC, carotid plaque, and cIMT to predict self-reported prevalent CVD.
PMCID: PMC3538165  PMID: 23107930
carotid intima media thickness; coronary artery calcification; kidney; plaque
5.  Impact of metabolic syndrome and its components on cardiovascular disease event rates in 4900 patients with type 2 diabetes assigned to placebo in the field randomised trial 
Patients with the metabolic syndrome are more likely to develop type 2 diabetes and may have an increased risk of cardiovascular disease (CVD) events.We aimed to establish whether CVD event rates were influenced by the metabolic syndrome as defined by the World Health Organisation (WHO), the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) and the International Diabetes Federation (IDF) and to determine which component(s) of the metabolic syndrome (MS) conferred the highest cardiovascular risk in in 4900 patients with type 2 diabetes allocated to placebo in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial.
Research design and methods
We determined the influence of MS variables, as defined by NCEP ATPIII, IDF and WHO, on CVD risk over 5 years, after adjustment for CVD, sex, HbA1c, creatinine, and age, and interactions between the MS variables in a Cox proportional-hazards model.
About 80% had hypertension, and about half had other features of the metabolic syndrome (IDF, ATPIII). There was no difference in the prevalence of metabolic syndrome variables between those with and without CVD at study entry. The WHO definition identified those at higher CVD risk across both sexes, all ages, and in those without prior CVD, while the ATPIII definition predicted risk only in those aged over 65 years and in men but not in women. Patients meeting the IDF definition did not have higher risk than those without IDF MS.
CVD risk was strongly influenced by prior CVD, sex, age (particularly in women), baseline HbA1c, renal dysfunction, hypertension, and dyslipidemia (low HDL-c, triglycerides > 1.7 mmol/L). The combination of low HDL-c and marked hypertriglyceridemia (> 2.3 mmol/L) increased CVD risk by 41%. Baseline systolic blood pressure increased risk by 16% per 10 mmHg in those with no prior CVD, but had no effect in those with CVD. In those without prior CVD, increasing numbers of metabolic syndrome variables (excluding waist) escalated risk.
Absence of the metabolic syndrome (by the WHO definition) identifies diabetes patients without prior CVD, who have a lower risk of future CVD events. Hypertension and dyslipidemia increase risk.
PMCID: PMC3286386  PMID: 22104275
6.  Increasing Use of Vitamin D Supplementation in the Chronic Renal Insufficiency Cohort Study 
This study examined rates and determinants of vitamin D supplementation among Chronic Renal Insufficiency Cohort (CRIC) participants and determined the association between dose and 25-hydroxyvitamin D (25(OH)D) level. The 2010 Institute of Medicine Report noted a significant increase in vitamin D supplementation in the general population, but use in chronic kidney disease (CKD) is unknown.
CRIC is a multicenter prospective observational cohort study of 3,939 participants with a median baseline age of 60 and an estimated glomerular filtration rate (eGFR) of 42.1 mL/minute per 1.73 m2. Of the cohort, 54.9% was male, 42.1% were Black, and 48.4% were diabetic. Multivariable logistic generalized estimating equations were used to examine determinants of supplementation use assessed annually between 2003 and 2011. Cross-sectional linear regression models, based on a subset of 1,155 participants, assessed associations between supplement dose and 25(OH)D level, measured by high-performance liquid chromatography coupled with tandem mass spectrometry.
The proportion of participants reporting supplement use increased (P < .0001), from 10% at baseline to 44% at 7-year follow-up visits. This was largely due to initiation of products containing only ergocalciferol or cholecalciferol. The odds of supplementation were greater in older, female, non-Black, married participants with greater education and lower body mass index. Among participants taking supplementation, dose was positively associated with 25(OH)D level, adjusted for race, season, diabetes, dietary intake, eGFR, and proteinuria. Only 3.8% of non-Black and 16.5% of Black participants taking a supplement were deficient (<20 ng/mL), whereas 22.7% of non-Black and 62.4% of Black participants not reporting supplement use were deficient.
Vitamin D supplementation rates rose significantly among CRIC participants over 7 years of follow-up and were associated with greater serum 25(OH)D levels. Studies of vitamin D levels on clinical outcomes in CKD and future vitamin D interventional studies should consider these changes in supplementation practices.
PMCID: PMC4023561  PMID: 24613295
7.  “Association between moderate renal insufficiency and cardiovascular events in a general population: Tehran lipid and glucose study” 
BMC Nephrology  2012;13:59.
Chronic kidney disease(CKD) has been proposed as a risk factor for cardiovascular disease (CVD). There is conflicting evidence among community based studies regarding the association between CKD and CVD. Furthermore, in order to assess the possible interaction between CKD and BMI, we also examined the association between CKD and CVD, across different BMI categories.
The risk of CVD events was evaluated in a large cohort of participants selected from the Tehran Lipid and Glucose Study. Participants(mean age, 47.4 years) free of previous CVD were followed up for 9.1 years. GFR ml/min per 1.73 m2 was estimated using the MDRD formula.
Of the 6,209 participants, 22.2%(1381) had CKD with eGFR ml/min per 1.73 m2 <60 at baseline. Almost all of them (99%) were in stage 3a. Moderate renal insufficiency only predicted CVD outcomes independently when we adjusted for age and sex. After further adjustment, the presence of moderate CKD lost its statistical significance to confer an independent increased risk of CVD events with a hazard ratio of: HR: 1.14, CI 95% 0.91-1.42. Furthermore, when participants were categorized according to CKD status and BMI groups, after further adjustment, no interaction was found(P = 0.2).
CKD was not an independent risk factor for CVD events in a community-based study in a Tehranian population and the higher prevalence of CVD in subjects with mild to moderate renal insufficiency might be due to the co-occurrence of traditional CVD risk factors in this group.
PMCID: PMC3413571  PMID: 22799559
Chronic kidney disease; Cardiovascular disease; Body mass index; Glomerular filtration rate; General population
8.  Chronic Kidney Disease as a Predictor of Cardiovascular Disease (From the Framingham Heart Study) 
Chronic kidney disease (CKD) is a risk factor for cardiovascular disease (CVD), although shared risk factors may mediate much of the association. We related CKD and CVD in the setting of specific CVD risk factors and determined whether more advanced CKD was a CVD risk equivalent. The Framingham Heart Study original cohort (n=2471, mean age 68 years, 58.9% women) was studied. Glomerular filtration rate (eGFR) was estimated using the simplified Modification of Diet in Renal Disease Study equation. CKD was defined as eGFR < 59 mL/min per 1.73 m2 (women) and < 64 (men) and Stage 3b CKD defined as eGFR 30-44 (women) and 30-50 (men). Cox Proportional Hazard models adjusting for CVD risk factors were used to relate CKD to CVD. We tested for effect modification by CVD risk factors. Overall, 23.2% of the study sample had CKD (n=574; mean eGFR 50 mL/min per 1.73 m2) and 5.3% had Stage 3b CKD (n=131; mean eGFR 42 mL/min per 1.73 m2). In multivariable models (mean follow-up time 16 years), Stage 3 CKD was marginally associated with CVD (HR=1.17, 95% CI 0.99-1.38, p=0.06), whereas Stage 3b CKD was associated with CVD [HR=1.41, 95% CI 1.05-1.91, p=0.02]. Upon testing CVD risk equivalency, the risk of CVD for Stage 3b CKD among participants with prior CVD was significantly lower as compared to participants with prior CVD and no Stage 3b CKD (age- and sex-adjusted HR for CVD = 0.66 [95% CI 0.47 to 0.91], p=0.01). Low HDL modified the association between CKD and CVD (p-value=0.004 for interaction). Stage 3b CKD is associated with CVD but is not a CVD risk equivalent. In conclusion, CVD risk in the setting of CKD is higher in the setting of low HDL cholesterol.
PMCID: PMC2517213  PMID: 18572034
9.  The Association of Chronic Kidney Disease and Metabolic Syndrome with Incident Cardiovascular Events: Multiethnic Study of Atherosclerosis 
Background. There is an association between chronic kidney disease (CKD) and metabolic syndrome (MetS). We examined the joint association of CKD and MetS with incident cardiovascular (CVD) events in the Multiethnic Study of Atherosclerosis (MESA) cohort. Methods. We analyzed 2,283 Caucasians, 363 Chinese, 1,449 African-Americans, and 1,068 Hispanics in the MESA cohort. CKD was defined by cystatin C estimated glomerular filtration rate ≤ 60 mL/min/1.73 m2 and MetS was defined by NCEP criteria. Cox proportional regression adjusting for age, ethnicity, gender, study site, education, income, smoking, alcohol use, physical activity, and total and LDL cholesterol was performed to assess the joint association of CKD and MetS with incident CVD events. Participants were divided into four groups by presence of CKD and/or MetS and compared to the group without CKD and MetS (CKD−/MetS−). Tests for additive and multiplicative interactions between CKD and MetS and prediction of incident CVD were performed. Results. During follow-up period of 5.5 years, 283 participants developed CVD. Multivariate Cox regression analysis demonstrated that CKD and MetS were independent predictors of CVD (hazard ratio, 2.02 for CKD, and 2.55 for MetS). When participants were compared to the CKD−/MetS− group, adjusted HR for the CKD+/MetS+ group was 5.56 (95% CI 3.72–8.12). There was no multiplicative interaction between CKD and MetS (P = 0.2); however, there was presence of additive interaction. The relative excess risk for additive interaction (RERI) was 2.73, P = 0.2, and the attributable portion (AP) was 0.49 (0.24–0.74). Conclusion. Our findings illustrate that the combination of CKD and MetS is a strong predictor of incident clinical cardiovascular events due to presence of additive interaction between CKD and MetS.
PMCID: PMC3154776  PMID: 21860804
10.  Lung Function and Heart Disease in American Indian Adults with High Frequency of Metabolic Abnormalities (From the Strong Heart Study) 
The American journal of cardiology  2014;114(2):312-319.
The associations of pulmonary function with cardiovascular disease (CVD) independent of diabetes mellitus (DM) and metabolic syndrome have not been examined in a population-based setting. We examined prevalence and incidence CVD in relation to lower pulmonary function in the Strong Heart Study 2nd examination (1993-1995) in 352 CVD and 2873 non-CVD adults free of overt lung disease (mean age 60 years). Lung function was assessed by standard spirometry. Participants with metabolic syndrome or DM with or without CVD had lower pulmonary function than participants without these conditions after adjustment for hypertension, age, gender, abdominal obesity, smoking, physical activity index and study field center. CVD participants with DM had significantly lower FVC than participants with CVD alone. Significant associations were observed between reduced pulmonary function, preclinical CVD and prevalent CVD after adjustment for multiple CVD risk factors. During follow-up (median 13.3 years), pulmonary function did not predict CVD incidence, it predicted CVD mortality. Among 3225 participants, 412 (298 without baseline CVD) died from CVD by the end of 2008. In models adjusted for multiple CVD risk factors, DM, metabolic syndrome and baseline CVD, compared to highest quartile of lung function, lower lung function predicted CVD mortality (RR up to 1.5, 95% CI 1.1-2.0, p<0.05). In conclusion, a population with a high prevalence of DM and metabolic syndrome, lower lung function was independently associated with prevalent clinical and preclinical CVD, and its impairment predicted CVD mortality. Additional research is needed to identify mechanisms linking metabolic abnormalities, low lung function and CVD.
PMCID: PMC4093833  PMID: 24878118
lung function; cardiovascular diseases; diabetes mellitus; metabolic syndrome
11.  Chronic Kidney Disease and Prevalent Atrial Fibrillation: The Chronic Renal Insufficiency Cohort (CRIC) 
American heart journal  2010;159(6):1102-1107.
The epidemiology of atrial fibrillation (AF) has been mainly investigated in patients with end-stage renal disease (ESRD), with limited data on less advanced chronic kidney disease (CKD) stages.
A total of 3267 adult participants (50% non-Hispanic blacks, 46% females) with CKD from the Chronic Renal Insufficiency Cohort (CRIC) were included in this study. None of the study participants had been on dialysis. Those with self-identified race/ethnicity other than non-Hispanic black or white (N=323) or those without ECG data (N=22) were excluded. AF was ascertained by a 12-lead electrocardiogram (ECG) and self-report. Age- sex- race/ethnicity-specific prevalence rates of AF were estimated and compared between subgroups. Cross sectional associations and correlates with prevalent AF were examined using unadjusted and multivariable adjusted logistic regression analysis.
The mean estimated glomerular filtration rate (GFR) was 43.6 (±13.0) ml/min/1.73 m2. AF was present in 18% of the study population and in more than 25% of those 70 years or older. In multivariable adjusted models, 1-SD increase in age (11 years) [odds ratio (OR) and CI 95%: 1.27 (1.13, 1.43), P<0.0001], female sex [0.80 (0.65, 0.98), P=0.0303], smoking (former vs. never) [1.34 (1.08, 1.66), P= 0.0081], history of heart failure [3.28 (2.47, 4.36), P<0.001], and history of cardiovascular disease [1.94 (1.56, 2.43), P<0.0001] were significantly associated with AF. Race/ethnicity, hypertension, diabetes, body mass index, physical activity, education, high sensitivity C-reactive protein, total cholesterol, and alcohol intake were not significantly associated with AF. An estimated GFR <45 ml/min/1.73 m2 was associated with AF in an unadjusted model [1.35 (1.13–1.62)); P=0.0010)], but not after multivariable adjustment [1.12 (0.92– 1.35), P=0.2710].
Nearly one in five participants in CRIC, a national study of CKD, had evidence for AF at study entry, a prevalence similar to that reported among patients with ESRD and 2–3 times of that reported in the general population. Risk factors for AF in this CKD population do not mirror those reported in the general population.
PMCID: PMC2891979  PMID: 20569726
12.  Predictors of high sensitivity cardiac troponin T in chronic kidney disease patients: a cross-sectional study in the chronic renal insufficiency cohort (CRIC) 
BMC Nephrology  2013;14:229.
Cardiac troponin T is independently associated with cardiovascular events and mortality in patients with chronic kidney disease (CKD). Serum levels of high sensitivity cardiac troponin T (hs-TnT) reflect subclinical myocardial injury in ambulatory patients. We sought to determine the distribution and predictors of hs-TnT in CKD patients without overt cardiovascular disease (CVD).
We studied 2464 participants within the multi-ethnic Chronic Renal Insufficiency Cohort (CRIC) who did not have self-reported CVD. We considered renal and non-renal factors as potential determinants of hs-TnT, including demographics, comorbidities, left ventricular (LV) mass, serologic factors, estimated glomerular filtration rate (eGFR) and albumin to creatinine ratio.
Hs-TnT was detectable in 81% of subjects, and the median (IQR) hs-TnT was 9.4 pg/ml (4.3-18.3). Analysis was performed using Tobit regression, adjusting for renal and non-renal factors. After adjustment, lower eGFR was associated with higher expected hs-TnT; participants with eGFR < 30 ml/min/1.73 m2 had 3-fold higher expected hs-TnT compared to subjects with eGFR > 60. Older age, male gender, black race, LV mass, diabetes and higher blood pressure all had strong, independent associations with higher expected hs-TnT.
Knowledge of the determinants of hs-TnT in this cohort may guide further research on the pathology of heart disease in patients with CKD and help to stratify sub-groups of CKD patients at higher cardiovascular risk.
PMCID: PMC4016297  PMID: 24148285
Troponin T; Chronic kidney disease; Cardiovascular disease
13.  Renal Dysfunction, Metabolic Syndrome and Cardiovascular Disease Mortality 
Background. Renal disease is commonly described as a complication of metabolic syndrome (MetS) but some recent studies suggest that Chronic Kidney disease (CKD) may actually antecede MetS. Few studies have explored the predictive utility of co-clustering CKD with MetS for cardiovascular disease (CVD) mortality. Methods. Data from a nationally representative sample of United States adults (NHANES) was utilized. A sample of 13115 non-pregnant individuals aged ≥35 years, with available follow-up mortality assessment was selected. Multivariable Cox Proportional hazard regression analysis techniques explored the relationship between co-clustered CKD, MetS and CVD mortality. Bayesian analysis techniques tested the predictive accuracy for CVD Mortality of two models using co-clustered MetS and CKD and MetS alone. Results. Co-clustering early and late CKD respectively resulted in statistically significant higher hazard for CVD mortality (HR = 1.80, CI = 1.45–2.23, and HR = 3.23, CI = 2.56–3.70) when compared with individuals with no MetS and no CKD. A model with early CKD and MetS has a higher predictive accuracy (72.0% versus 67.6%), area under the ROC (0.74 versus 0.66), and Cohen's kappa (0.38 versus 0.21) than that with MetS alone. Conclusion. The study findings suggest that the co-clustering of early CKD with MetS increases the accuracy of risk prediction for CVD mortality.
PMCID: PMC2911619  PMID: 20700408
14.  Estimated GFR and Incident Cardiovascular Disease Events in American Indians: The Strong Heart Study 
In populations with high prevalence of diabetes and obesity, estimating glomerular filtration rate (GFR) by using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation may predict cardiovascular disease risk better than by using the Modification of Diet in Renal Disease (MDRD) Study equation.
Study design
Longitudinal cohort study comparing the association of GFR estimated using either the CKD-EPI or MDRD Study equations with incident cardiovascular disease outcomes.
Setting and participants
American Indians participating in the Strong Heart Study, a longitudinal population-based cohort with high prevalences of diabetes, cardiovascular disease, and CKD.
Predictor or factor
eGFR predicted using the CKD-EPI and MDRD Study equations.
Fatal and nonfatal cardiovascular events, consisting of coronary heart disease, stroke, and heart failure.
The association between eGFR and outcomes was explored in Cox proportional hazards models, adjusted for traditional risk factors and albuminuria; the net reclassification index and integrated discrimination improvement were determined for the CKD-EPI versus MDRD Study equations.
Among 4549 participants, diabetes was present in 45%, cardiovascular disease in 7%, and stage 3–5 CKD in 10%. Over a median of 15 years, there were 1280 cases of incident CVD, 929 of incident coronary heart disease, 305 of incident stroke, and 381 of incident heart failure. Reduced eGFR (<90 mL/min/1.73 m2) was associated with adverse events in most models. Compared with the MDRD Study equation, the CKD-EPI equation correctly reclassified 17.0% of 2,151 participants without incident CVD to a lower risk (higher eGFR) category and 1.3% (n=28) were incorrectly reclassified to a higher risk (lower eGFR) category.
Single measurements of eGFR and albuminuria at study visits.
Although eGFR based on either equation had similar associations with incident cardiovascular disease, coronary heart disease, stroke, and heart failure events, among those not having events, reclassification of participants to eGFR categories was superior using the CKD-EPI equation compared with the MDRD Study equation.
PMCID: PMC3473098  PMID: 22841159
cardiovascular disease risk; chronic kidney disease; estimated glomerular filtration rate; Strong Heart Study
15.  Association of Non-alcoholic Fatty Liver Disease with Chronic Kidney Disease: A Systematic Review and Meta-analysis 
PLoS Medicine  2014;11(7):e1001680.
In a systematic review and meta-analysis, Giovanni Musso and colleagues examine the association between non-alcoholic fatty liver disease and chronic kidney disease.
Please see later in the article for the Editors' Summary
Chronic kidney disease (CKD) is a frequent, under-recognized condition and a risk factor for renal failure and cardiovascular disease. Increasing evidence connects non-alcoholic fatty liver disease (NAFLD) to CKD. We conducted a meta-analysis to determine whether the presence and severity of NAFLD are associated with the presence and severity of CKD.
Methods and Findings
English and non-English articles from international online databases from 1980 through January 31, 2014 were searched. Observational studies assessing NAFLD by histology, imaging, or biochemistry and defining CKD as either estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 or proteinuria were included. Two reviewers extracted studies independently and in duplicate. Individual participant data (IPD) were solicited from all selected studies. Studies providing IPD were combined with studies providing only aggregate data with the two-stage method. Main outcomes were pooled using random-effects models. Sensitivity and subgroup analyses were used to explore sources of heterogeneity and the effect of potential confounders. The influences of age, whole-body/abdominal obesity, homeostasis model of insulin resistance (HOMA-IR), and duration of follow-up on effect estimates were assessed by meta-regression. Thirty-three studies (63,902 participants, 16 population-based and 17 hospital-based, 20 cross-sectional, and 13 longitudinal) were included. For 20 studies (61% of included studies, 11 cross-sectional and nine longitudinal, 29,282 participants), we obtained IPD. NAFLD was associated with an increased risk of prevalent (odds ratio [OR] 2.12, 95% CI 1.69–2.66) and incident (hazard ratio [HR] 1.79, 95% CI 1.65–1.95) CKD. Non-alcoholic steatohepatitis (NASH) was associated with a higher prevalence (OR 2.53, 95% CI 1.58–4.05) and incidence (HR 2.12, 95% CI 1.42–3.17) of CKD than simple steatosis. Advanced fibrosis was associated with a higher prevalence (OR 5.20, 95% CI 3.14–8.61) and incidence (HR 3.29, 95% CI 2.30–4.71) of CKD than non-advanced fibrosis. In all analyses, the magnitude and direction of effects remained unaffected by diabetes status, after adjustment for other risk factors, and in other subgroup and meta-regression analyses. In cross-sectional and longitudinal studies, the severity of NAFLD was positively associated with CKD stages. Limitations of analysis are the relatively small size of studies utilizing liver histology and the suboptimal sensitivity of ultrasound and biochemistry for NAFLD detection in population-based studies.
The presence and severity of NAFLD are associated with an increased risk and severity of CKD.
Please see later in the article for the Editors' Summary
Editors' Summary
Chronic kidney disease (CKD)—the gradual loss of kidney function—is becoming increasingly common. In the US, for example, more than 10% of the adult population (about 26 million people) and more than 25% of individuals older than 65 years have CKD. Throughout life, the kidneys perform the essential task of filtering waste products (from the normal breakdown of tissues and from food) and excess water from the blood to make urine. CKD gradually destroys the kidneys' filtration units, the rate of blood filtration decreases, and dangerous amounts of waste products build up in the blood. Symptoms of CKD, which rarely occur until the disease is very advanced, include tiredness, swollen feet, and frequent urination, particularly at night. There is no cure for CKD, but progression of the disease can be slowed by controlling high blood pressure and diabetes (two risk factors for CKD), and by adopting a healthy lifestyle. The same interventions also reduce the chances of CKD developing in the first place.
Why Was This Study Done?
CKD is associated with an increased risk of end-stage renal (kidney) disease and of cardiovascular disease. These life-threatening complications are potentially preventable through early identification and treatment of CKD. Because early recognition of CKD has the potential to reduce its health-related burden, the search is on for new modifiable risk factors for CKD. One possible new risk factor is non-alcoholic fatty liver disease (NAFLD), which, like CKD is becoming increasingly common. Healthy livers contain little or no fat but, in the US, 30% of the general adult population and up to 70% of patients who are obese or have diabetes have some degree of NAFLD, which ranges in severity from simple fatty liver (steatosis), through non-alcoholic steatohepatitis (NASH), to NASH with fibrosis (scarring of the liver) and finally cirrhosis (extensive scarring). In this systematic review and meta-analysis, the researchers investigate whether NAFLD is a risk factor for CKD by looking for an association between the two conditions. A systematic review identifies all the research on a given topic using predefined criteria, meta-analysis uses statistical methods to combine the results of several studies.
What Did the Researchers Do and Find?
The researchers identified 33 studies that assessed NAFLD and CKD in nearly 64,000 participants, including 20 cross-sectional studies in which participants were assessed for NAFLD and CKD at a single time point and 13 longitudinal studies in which participants were assessed for NAFLD and then followed up to see whether they subsequently developed CKD. Meta-analysis of the data from the cross-sectional studies indicated that NAFLD was associated with a 2-fold increased risk of prevalent (pre-existing) CKD (an odds ratio [OR]of 2.12; an OR indicates the chance that an outcome will occur given a particular exposure, compared to the chance of the outcome occurring in the absence of that exposure). Meta-analysis of data from the longitudinal studies indicated that NAFLD was associated with a nearly 2-fold increased risk of incident (new) CKD (a hazard ratio [HR] of 1.79; an HR indicates often a particular event happens in one group compared to how often it happens in another group, over time). NASH was associated with a higher prevalence and incidence of CKD than simple steatosis. Similarly, advanced fibrosis was associated with a higher prevalence and incidence of CKD than non-advanced fibrosis.
What Do These Findings Mean?
These findings suggest that NAFLD is associated with an increased prevalence and incidence of CKD and that increased severity of liver disease is associated with an increased risk and severity of CKD. Because these associations persist after allowing for established risk factors for CKD, these findings identify NAFLD as an independent CKD risk factor. Certain aspects of the studies included in this meta-analysis (for example, only a few studies used biopsies to diagnose NAFLD; most used less sensitive tests that may have misclassified some individuals with NAFLD as normal) and the methods used in the meta-analysis may limit the accuracy of these findings. Nevertheless, these findings suggest that individuals with NAFLD should be screened for CKD even in the absence of other risk factors for the disease, and that better treatment of NAFLD may help to prevent CKD.
Additional Information
Please access these websites via the online version of this summary at
The US National Kidney and Urologic Diseases Information Clearinghouse provides information about all aspects of kidney disease; the US National Digestive Diseases Information Clearinghouse provides information about non-alcoholic liver disease
The US National Kidney Disease Education Program provides resources to help improve the understanding, detection, and management of kidney disease (in English and Spanish)
The UK National Health Service Choices website provides information for patients on chronic kidney disease, including some personal stories, and information on non-alcoholic fatty liver disease
The US National Kidney Foundation, a not-for-profit organization, provides information about chronic kidney disease (in English and Spanish)
The not-for-profit UK National Kidney Federation provides support and information for patients with kidney disease and for their carers
The British Liver Trust, a not-for-profit organization, provides information about non-alcoholic fatty liver disease, including a patient story
PMCID: PMC4106719  PMID: 25050550
16.  Factors Associated With Depressive Symptoms and Use of Antidepressant Medications Among Participants in the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC Studies 
Depressive symptoms are correlated with poor health outcomes in adults with chronic kidney disease (CKD). The prevalence, severity, and treatment of depressive symptoms and potential risk factors, including level of kidney function, in diverse populations with CKD have not been well studied.
Study Design
Cross-sectional analysis
Settings and Participants
Participants at enrollment into the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC (H-CRIC) Studies. CRIC enrolled Hispanics and non-Hispanics at seven centers from 2003-2007, and H-CRIC enrolled Hispanics at the University of Illinois from 2005-2008.
Depressive symptoms measured by Beck Depression Inventory (BDI)
Demographic and clinical factors
Elevated depressive symptoms (BDI >= 11) and antidepressant medication use
Among 3853 participants, 28.5% had evidence of elevated depressive symptoms and 18.2% were using antidepressant medications; 30.8% of persons with elevated depressive symptoms were using antidepressants. The prevalence of elevated depressive symptoms varied by level of kidney function: 25.2% among participants with eGFR ≥ 60 ml/min/1.73m2, and 35.1% of those with eGFR < 30 ml/min/1.73m2. Lower eGFR (OR per 10 ml/min/1.73m2 decrease, 1.09; 95% CI, 1.03-1.16), Hispanic ethnicity (OR, 1.65; 95% CI, 1.12-2.45), and non-Hispanic black race (OR, 1.43; 95% CI, 1.17-1.74) were each associated with increased odds of elevated depressive symptoms after controlling for other factors. In regression analyses incorporating BDI score, while female sex was associated with a greater odds of antidepressant use, Hispanic ethnicity, non-Hispanic black race, and higher levels of urine albumin were associated with decreased odds of antidepressant use (p<0.05 for each).
Absence of clinical diagnosis of depression and use of non-pharmacologic treatments
Although elevated depressive symptoms were common in individuals with CKD, use of antidepressant medications is low. African Americans, Hispanics, and individuals with more advanced CKD had higher odds of elevated depressive symptoms and lower odds of antidepressant medication use.
PMCID: PMC3378778  PMID: 22497791
17.  Gout and subsequent increased risk of cardiovascular mortality in non-diabetics aged 50 and above: a population-based cohort study in Taiwan 
Limited data are available on the risk ratios for fatal cardiovascular disease (CVD) outcome from gout and chronic kidney disease (CKD) in non-diabetic individuals.
Nationwide population-based retrospective prospective study with a 5-year follow-up to investigate the association between physician-diagnosed gout and CKD in non-diabetics aged 50 and above who had no pre-existing serious CVD and the subsequent risk of death from CVD. Hazard ratios (HR) of CVD mortality were adjusted for gender, age, smoking- and alcoholism-related diagnoses, hypertension, hyperlipidemia, atrial fibrillation and Charlson’s comorbidity index score.
A case cohort (n=164,463) having gout and a control cohort (n= 3,694,377) having no gout were formed. The prevalence of gout in this study was 4.26% whereas that of gout plus CKD was 8.17%. Male to female ratio among the individuals with gout was 3.2:1. The relative risk (RR) of subsequent cardiovascular mortality between the case and control cohort was 1.71 (95% confidence interval (CI), 1.66-1.75). The presence of CKD in nondiabetic subjects with no gout (control group) has a RR of CVD mortality at 3.05 (95% CI, 2.94-3.15). The presence of gout has protective effect on subjects with CKD with a RR of 1.84 (95% CI, 1.71-1.98). As compared with individuals with no gout, the adjusted HR (aHR) for CVD mortality among the individuals with gout was 1.10 (95% CI 1.07-1.13). In a Cox model, when compared with subjects having neither gout nor CKD, the aHR in subjects with no gout but with CKD is 1.76 (95% CI, 1.70-1.82); in subjects with gout but without CKD, 1.10 (1.07-1.13); interestingly, the aHR is attenuated in subjects with concomitant gout plus CKD which is 1.38 (1.29-1.48).
Among non-diabetic individuals aged 50 years or above who had no preceding serious CVD, those with gout were 1.1 times more likely to die from CVD as were individuals without gout. The presence of gout appears to attenuate the risk of subsequent CV mortality in subjects with CKD. Further studies should focus on finding an explanation for the protective effect of gout on CV mortality in patients with CKD.
PMCID: PMC3556493  PMID: 23170782
18.  Prevalence and Awareness of CKD Among African Americans: The Jackson Heart Study 
Chronic kidney disease (CKD) leads to End Stage Renal Disease (ESRD) and is a growing epidemic throughout the world. In the United States, African Americans have an incidence of ESRD four times that of Whites.
Study Design
Cross Sectional to examine the prevalence and awareness of CKD in African Americans
Setting & Participants
Observational Cohort in the Jackson Heart Study (JHS)
CKD was defined as estimated glomerular filtration rate < 60 ml/min/1.73 m2, presence of albuminuria, or being on dialysis
Outcomes and Measurements
Data from the Jackson Heart Study (JHS) were analyzed. Medical history including disease awareness and drug therapy, anthropometric measurements, serum, and urine samples were obtained from JHS participants at the baseline visit. Associations between CKD prevalence and awareness and selected demographic, socioeconomic, healthcare access, and disease status parameters were assessed utilizing logistic regression models.
The prevalence of CKD in the JHS was 20%; CKD awareness was only 15.8%. Older participants had higher prevalence but were also more aware of CKD. Hypertension, diabetes, cardiovascular disease (CVD), hypercholesterolemia, hypertriglyceridemia, increasing age and waist circumference as well as being single or less physically active were associated with CKD. Only advancing of CKD stage was associated with awareness.
Cross-sectional assessment, single urine measurement
The JHS has a high prevalence and low awareness of CKD, especially those with less severe disease status. This emphasizes the need for earlier diagnosis and increased education of health care providers and the general population.
PMCID: PMC2668959  PMID: 19166799
renal insufficiency; proteinuria; African American; chronic disease; epidemiology; population
19.  Diabetic Cardiovascular Disease Predicts Chronic Kidney Disease Awareness in the Kidney Early Evaluation Program 
Cardiorenal Medicine  2011;1(1):45-52.
Lack of chronic kidney disease (CKD) awareness is common. Recent data suggest that the presence of concurrent diabetes may heighten CKD awareness, but current data have not supported the hypothesis that healthcare delivery or insurance status improves awareness in the diabetic population. Diabetes is associated with high cardiovascular disease (CVD) morbidity, especially in patients with CKD. We hypothesized that a highly prevalent co-morbid condition such as CVD in patients with diabetes would predict CKD awareness.
We utilized data from the National Kidney Foundation-Kidney Early Evaluation Program (KEEPTM), a large screening program designed to identify high-risk individuals for CKD and promote awareness.
Among 77,077 participants, CKD was identified in 20,200 and diabetes in 23,082. Prevalence of CVD was higher in participants with than without diabetes (39.5 vs. 22.0%) and in stage 3–5 compared to stage 1–2 CKD (43.3 vs. 34.4%). Patients with diabetes and CVD had a higher level of awareness than those without diabetes (8.2 vs. 2.2%). Among patients with diabetes and CVD, the presence of congestive heart failure was a better predictor of awareness [odds ratio (OR) 1.84; 95% confidence interval (CI) 1.40–2.43] than endpoints such as myocardial infarction or stroke [OR 1.35 (95% CI 1.04–1.73) and OR 1.34 (95% CI 1.04–1.72), respectively].
While prevalence of CKD awareness remained low, our data suggest that in patients with diabetes the presence of CVD was associated with increased awareness in a targeted screening program for CKD awareness.
PMCID: PMC3101520  PMID: 22258465
Cardiovascular disease; Chronic kidney disease; Diabetes mellitus; KEEP
20.  Time-updated systolic blood pressure and the progression of chronic kidney disease: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study 
Annals of internal medicine  2015;162(4):258-265.
Blood pressure (BP) is often inadequately controlled in patients with chronic kidney disease (CKD). Previous reports of the longitudinal association between achieved level of BP and end-stage renal disease (ESRD) have not incorporated time-updated BP with appropriate adjustment for known confounders.
To assess the association between baseline and time-updated systolic BP (SBP) with the progression of CKD.
Observational, prospective cohort study ( identifier: NCT00304148)
Seven US clinical centers
Participants of the Chronic Renal Insufficiency Cohort (CRIC) Study (N=3,708) followed for a median (25th, 75th percentiles) of 5.7 (4.6, 6.7) years
The mean of three seated SBP measurements were used as the visit-specific SBP. SBP was time-updated as the mean of that visit and all prior visits. Outcomes were ESRD and the composite renal endpoint of ESRD (dialysis or transplantation) or halving of the estimated glomerular filtration rate (eGFR). Analyses investigating baseline and time-updated SBP utilized traditional Cox proportional hazards models and marginal structural models, respectively.
SBP was ≥130 mmHg at all study visits in 19.2% of participants, and ≥140 mmHg in 10.6%. The hazard ratio (95% confidence interval) for ESRD among participants with SBP 130–139 mmHg, compared to SBP <120 mmHg, was 1.46 (1.13–1.88) using only baseline data, and was 2.37 (1.48–3.80) using all available time-updated data. Among those with SBP ≥140 mmHg, corresponding hazard ratios were 1.46 (1.18–1.88) and 3.37 (2.26–5.03), respectively.
SBP was measured once annually, and the CRIC Study cohort is not a random sample.
Among participants in the CRIC Study, time-updated SBP over 130 mmHg was more strongly associated with progression of CKD than analyses based on baseline SBP.
The CRIC Study is funded under cooperative agreements from the National Institute of Diabetes and Digestive and Kidney Diseases, Clinical Translational Science Awards, and other NIH grants.
PMCID: PMC4404622  PMID: 25686166
21.  Baseline characteristics and prevalence of cardiovascular disease in newly visiting or referred chronic kidney disease patients to nephrology centers in Japan: a prospective cohort study 
BMC Nephrology  2013;14:152.
About 39,000 patients were newly prescribed renal replacement therapy in Japan in 2011, resulting in a total of more than 300,000 patients being treated with dialysis. This high prevalence of treated end stage kidney disease (ESKD) patients is an emergent problem that requires immediate attention. We launched a prospective cohort study to evaluate population specific characteristics of the progression of chronic kidney disease (CKD). In this report, we describe the baseline characteristics and risk factors for cardiovascular disease (CVD) prevalence among this cohort.
New patients from 16 nephrology centers who were older than 20 years of age and who visited or were referred for the treatment of CKD stage 2–5, but were not on dialysis therapy, were recruited in this study. At enrollment, medical history, lifestyle behaviors, functional status and current medications were recorded, and blood and urine samples were collected. Estimated glomerular filtration rate (eGFR) was calculated by a modified three-variable equation.
We enrolled 1138 patients, 69.6% of whom were male, with a mean age of 68 years. Compared with Western cohorts, patients in this study had a lower body mass index (BMI) and higher proteinuria. The prevalence of CVD was 26.8%, which was lower than that in Western cohorts but higher than that in the general Japanese population. Multivariate analysis demonstrated the following association with CVD prevalence: hypertension (adjusted odds ratio (aOR) 3.57; 95% confidence interval (CI) 1.82-7.02); diabetes (aOR 2.45; 95% CI 1.86-3.23); hemoglobin level less than 11 g/dl (aOR 1.61; 95% CI 1.21-2.15); receiving anti-hypertensive agents (aOR 3.54; 95% CI 2.27-5.53); and statin therapy (aOR 2.73; 95% CI 2.04-3.66). The combination of decreased eGFR and increased proteinuria was also associated with a higher prevalence of CVD.
The participants in this cohort had a lower BMI, higher proteinuria and lower prevalence of CVD compared with Western cohorts. Lower eGFR and high proteinuria were associated with CVD prevalence. Prospective follow up of these study patients will contribute to establishment of individual population-based treatment of CKD.
PMCID: PMC3723419  PMID: 23865418
Chronic kidney disease; Cohort study; Epidemiology; Cardiovascular disease; Nephrologist
22.  Uric Acid and Long-term Outcomes in CKD 
Hyperuricemia is prevalent in chronic kidney disease (CKD); however data are limited on the relationship of uric acid levels with long term outcomes in this patient population.
Study Design
Cohort Study
Setting & Participants
The Modification of Diet in Renal Disease (MDRD) Study was a randomized controlled trial (N=840), conducted 1989–1993, to examine the effects of strict blood pressure control and dietary protein restriction on progression of stage 3–4 CKD. This analysis included 838 patients.
Uric acid
Outcomes & Measurements
The study evaluated the association of baseline uric acid levels with all-cause mortality, cardiovascular (CVD) mortality, and kidney failure.
Mean (SD) age was 52 (12) years, glomerular filtration rate was 33 (12) ml/min/1.73m2, and uric acid was 7.63 (1.66) mg/dl. During a median follow-up of 10 years, 208 (25%) participants died of any cause, 127 (15%) from CVD, and 553 (66%) reached kidney failure. In multivariate models, the highest tertile of uric acid was associated with increased risk of all-cause (HR, 1.57 [95% CI, 1.07–2.32]) mortality, a trend towards CVD mortality (HR, 1.47 [95% CI, 0.90–2.39]) and no association with kidney failure (HR, 1.20 [95% CI, 0.95–1.51), compared to the lowest tertile. In continuous analyses, a 1-mg/dl higher uric acid was associated with 17% increased risk of all-cause (HR, 1.17 [95% CI, 1.05–1.30]), and 16% increased risk of CVD mortality (HR, 1.16 [95% CI, 1.01–1.33]), but was not associated with kidney failure (HR, 1.02 [95% CI, 0.97–1.07]).
Primary analyses were based on single measurement of uric acid. The results are primarily generalizable to relatively young white patients with predominantly non-diabetic CKD.
In stage 3–4 CKD, hyperuricemia appears to be an independent risk factor for all-cause and CVD mortality but not kidney failure.
PMCID: PMC2691553  PMID: 19303683
23.  Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study 
PLoS Medicine  2015;12(3):e1001809.
Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice.
Methods and Findings
A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with ≥3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR ≤ 60 ml/min/1.73 m2. Poisson regression was used to develop a risk score, externally validated on two independent cohorts.
In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7–6.7; median follow-up 6.1 y, range 0.3–9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was −2 (interquartile range –4 to 2). There was a 1:393 chance of developing CKD in the next 5 y in the low risk group (risk score < 0, 33 events), rising to 1:47 and 1:6 in the medium (risk score 0–4, 103 events) and high risk groups (risk score ≥ 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166–3,367); NNTH was 202 (95% CI 159–278) and 21 (95% CI 19–23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506–1462), 88 (95% CI 69–121), and 9 (95% CI 8–10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor.
The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3–12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6–8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria.
Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.
Editors’ Summary
About 35 million people are currently infected with HIV, the virus that causes AIDS. HIV destroys CD4 lymphocytes and other immune system cells, leaving infected individuals susceptible to other infections. HIV infection can be controlled, but not cured, using combination antiretroviral therapy (cART), and, nowadays, the life expectancy of many HIV-positive individuals is similar to that of HIV-negative people. HIV-positive individuals nevertheless experience some illnesses more frequently than HIV-negative people do. For example, up to a third of HIV-positive individuals develop chronic kidney disease (CKD), which is associated with an increased risk of cardiovascular disease and death. Persons with CKD may have an impaired effect of the filtration units in the kidneys that remove waste products and excess water from the blood to make urine, thereby leading to a reduced blood filtration rate (the estimated glomerular filtration rate [eGFR]) and waste product accumulation in the blood. Symptoms of CKD, which rarely occur until the disease is advanced, include tiredness, swollen feet, and frequent urination. Advanced stages of CKD cannot be cured, but its progression can be slowed by, for example, controlling hypertension (high blood pressure) and diabetes (two CDK risk factors) and by adopting a healthy lifestyle.
Why Was This Study Done?
The burden of CKD may increase among HIV-positive individuals as they age, and clinicians need to know which individuals are at high risk of developing CKD when choosing cART regimens for their patients. In addition, clinicians need to be able to identify those HIV-positive individuals at greatest risk of CKD so that they can monitor them for early signs of kidney disease. Some antiretroviral drugs—for example, tenofovir and atazanavir/ritonavir (a boosted protease inhibitor)—are associated with kidney damage. Clinicians may need to weigh the benefits and risks of giving such potentially nephrotoxic drugs to individuals who already have a high CKD risk. Here, the researchers develop and validate a simple, widely applicable risk score (a risk prediction model) for CKD among HIV-positive individuals and investigate the relationship between CKD and potentially nephrotoxic antiretroviral drugs among individuals with different CKD risk score profiles.
What Did the Researchers Do and Find?
To develop their CKD risk score, the researchers used clinical and demographic data collected from 17,954 HIV-positive individuals enrolled in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study who had an eGFR > 60 ml/min/1.73 m2 and were not taking a potentially nephrotoxic antiretroviral at baseline. During 103,185 person-years of follow-up, 641 individuals developed CKD. Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease predicted CKD. The researchers included these nine factors in their risk score model (which is available online) and defined three risk groups: low (risk score < 0), medium (risk score 0–4), and high (risk score ≥ 5) risk of CKD development in the next five years. Specifically, there was a 1 in 393, 1 in 47, and 1 in 6 chance of developing CKD in the next five years in the low, medium, and high risk groups, respectively. Because some patients started to use potentially nephrotoxic antiretroviral drugs during follow-up, the researchers were able to use their risk score model to calculate how many patients would have to be treated with one of these drugs for an additional patient to develop CKD over five years in each risk group. This “number needed to harm” (NNTH) for patients starting treatment with tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor was 739, 88, and 9 in the low, medium, and high risk groups, respectively. Finally, the researchers validated the accuracy of their risk score in two independent HIV study groups.
What Do These Findings Mean?
These findings provide a simple, validated risk score for CKD and indicate that the NNTH when starting potentially nephrotoxic antiretrovirals was low among HIV-positive individuals at the highest risk of CKD (i.e., treating just nine individuals with nephrotoxic antiretroviral drugs will likely lead to an additional case of CKD in five years). Although various aspects of the study, including the lack of data on race, limit the accuracy of these findings, these findings highlight the need for monitoring, screening, and chronic disease prevention to minimize the risk of HIV-positive individuals developing diabetes, hypertension, or cardiovascular disease, or becoming coinfected with hepatitis C, all of which contribute to the CKD risk score. Moreover, the development of a tool for estimating an individual’s five-year risk of developing CKD with or without the addition of potentially nephrotoxic antiretroviral drugs will enable clinicians and patients to weigh the benefits of certain antiretroviral drugs against the risk of CKD and make informed decisions about treatment options.
Additional Information
Please access these websites via the online version of this summary at
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
NAM/aidsmap provides basic information about HIV/AIDS, summaries of recent research findings on HIV care and treatment, and personal stories about living with AIDS/HIV
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including personal stories about living with HIV/AIDS
The World Health Organization provides information on all aspects of HIV/AIDS (in several languages), including its guidelines on the use of ART for treating and preventing HIV infection
The UNAIDS World AIDS Day Report 2014 provides up-to-date information about the AIDS epidemic and efforts to halt it
The UK National Health Service Choices website provides information for patients on chronic kidney disease, including some personal stories
The US National Kidney Foundation, a not-for-profit organization, provides information about chronic kidney disease (in English and Spanish)
A tool for calculating the CDK risk score developed in this study is available
Additional information about the D:A:D study is available
Amanda Mocroft and colleagues develop and validate a model for determining risk of developing chronic kidney disease for individuals with HIV if treated with different antiretroviral therapies.
PMCID: PMC4380415  PMID: 25826420
24.  Effects of Fenofibrate Treatment on Cardiovascular Disease Risk in 9,795 Individuals With Type 2 Diabetes and Various Components of the Metabolic Syndrome 
Diabetes Care  2009;32(3):493-498.
OBJECTIVE—We explored whether cardiovascular disease (CVD) risk and the effects of fenofibrate differed in subjects with and without metabolic syndrome and according to various features of metabolic syndrome defined by the Adult Treatment Panel III (ATP III) in subjects with type 2 diabetes in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study.
RESEARCH DESIGN AND METHODS—The prevalence of metabolic syndrome and its features was calculated. Cox proportional models adjusted for age, sex, CVD status, and baseline A1C levels were used to determine the independent contributions of metabolic syndrome features to total CVD event rates and the effects of fenofibrate.
RESULTS—More than 80% of FIELD participants met the ATP III criteria for metabolic syndrome. Each ATP III feature of metabolic syndrome, apart from increased waist circumference, increased the absolute risk of CVD events over 5 years by at least 3%. Those with marked dyslipidemia (elevated triglycerides ≥2.3 mmol/l and low HDL cholesterol) were at the highest risk of CVD (17.8% over 5 years). Fenofibrate significantly reduced CVD events in those with low HDL cholesterol or hypertension. The largest effect of fenofibrate to reduce CVD risk was observed in subjects with marked dyslipidemia in whom a 27% relative risk reduction (95% CI 9–42, P = 0.005; number needed to treat = 23) was observed. Subjects with no prior CVD had greater risk reductions than the entire group.
CONCLUSIONS—Metabolic syndrome components identify higher CVD risk in individuals with type 2 diabetes, so the absolute benefits of fenofibrate are likely to be greater when metabolic syndrome features are present. The highest risk and greatest benefits of fenofibrate are seen among those with marked hypertriglyceridemia.
PMCID: PMC2646035  PMID: 18984774
25.  Risk Factors for Peripheral Arterial Disease among Patients with Chronic Kidney Disease 
The American journal of cardiology  2012;110(1):136-141.
Patients with chronic kidney disease (CKD) have an increased risk of developing peripheral arterial disease (PAD). We examined the cross-sectional association between novel risk factors and prevalent PAD among patients with CKD. A total of 3,758 patients with an estimated glomerular filtration rate (eGFR) of 20-70 mL/min/1.73 m2 who participated in the chronic renal insufficiency cohort (CRIC) study were included in the current analysis. PAD was defined as an ankle-brachial index <0.9 or a history of arm or leg revascularization. After adjustment for age, sex, race, cigarette smoking, physical activity, history of hypertension and diabetes, pulse pressure, high-density lipoprotein cholesterol, eGFR, and CRIC clinical sites, several novel risk factors were significantly associated with PAD. For example, odds ratios (95% confidence intervals) for a one standard deviation higher level of risk factors were 1.18 (1.08–1.29) for log-transformed high sensitivity-C reactive protein, 1.18 (1.08–1.29) for white blood cell count, 1.15 (1.05–1.25) for fibrinogen, 1.13 (1.03–1.24) for uric acid, 1.14 (1.02–1.26) for hemoglobin A1c, 1.11 (1.00–1.23) for log-transformed homeostasis model assessment-insulin resistance, and 1.35 (1.18–1.55) for cystatin C. In conclusion, these data indicate that inflammation, prothrombotic state, oxidative stress, insulin resistance, and cystatin C were associated with an increased prevalence of PAD in patients with CKD. Further studies are warranted to examine the causal effect of these risk factors on PAD in CKD patients.
PMCID: PMC3586781  PMID: 22465315
peripheral arterial disease; novel risk factors; chronic kidney disease

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