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1.  Candidate Gene Association Study of Coronary Artery Calcification in Chronic Kidney Disease: Findings from the Chronic Renal Insufficiency Cohort Study 
To identify loci for coronary artery calcification (CAC) in patients with chronic kidney disease (CKD).
CKD is associated with increased CAC and subsequent coronary heart disease (CHD) but the mechanisms remain poorly defined. Genetic studies of CAC in CKD may provide a useful strategy for identifying novel pathways in CHD.
We performed a candidate gene study (~2,100 genes; ~50,000 SNPs) of CAC within the Chronic Renal Insufficiency Cohort (CRIC) Study (n=1,509; 57% European, 43% African ancestry). SNPs with preliminary evidence of association with CAC in CRIC were examined for association with CAC in PennCAC (n=2,560) and Amish Family Calcification Study (AFCS; n=784) samples. SNPs with suggestive replication were further analyzed for association with myocardial infarction (MI) in the Pakistan Risk of Myocardial Infarction study (PROMIS) (n=14,885).
Of 268 SNPs reaching P <5×10−4 for CAC in CRIC, 28 SNPs in 23 loci had nominal support (P <0.05 and in same direction) for CAC in PennCAC or AFCS. Besides chr9p21 and COL4A1, known loci for CHD, these included SNPs having reported GWAS association with hypertension (e.g., ATP2B1). In PROMIS, four of the 23 suggestive CAC loci (chr9p21, COL4A1, ATP2B1 and ABCA4) had significant associations with MI consistent with their direction of effect on CAC.
We identified several loci associated with CAC in CKD that also relate to MI in a general population sample. CKD imparts a high risk of CHD and may provide a useful setting for discovery of novel CHD genes and pathways.
PMCID: PMC3953823  PMID: 23727086
Coronary artery calcification (CAC); chronic kidney disease (CKD); Chronic Renal Insufficiency Cohort Study (CRIC); myocardial infarction (MI); risk factors; candidate genes; single nucleotide polymorphisms (SNPs)
2.  Mortality and morbidity during and after ALLHAT: Results by gender 
Hypertension  2013;61(5):977-986.
To determine whether an angiotensin-converting enzyme inhibitor (lisinopril) or calcium channel blocker (amlodipine) is superior to a diuretic (chlorthalidone) in reducing cardiovascular disease incidence in gender subgroups, we carried out a prespecified subgroup analysis of 15,638 female and 17,719 male participants in the Antihypertensive and Lipid-Lowering to Prevent Heart Attack Trial (ALLHAT). Total follow-up (active treatment + passive surveillance using national administrative databases to ascertain deaths and hospitalizations) was 8 to 13 years. The primary outcome was fatal coronary heart disease or nonfatal myocardial infarction. Secondary outcomes included all-cause mortality, stroke, combined cardiovascular disease (coronary heart disease death, nonfatal myocardial infarction, stroke, angina, coronary revascularization, heart failure, or peripheral vascular disease), and end-stage renal disease. In-trial rates of heart failure, stroke, and combined cardiovascular disease were significantly higher for lisinopril compared to chlorthalidone, and rates of heart failure were significantly higher for amlodipine compared to chlorthalidone in both men and women. There were no significant treatment gender interactions. These findings did not persist through the extension period with the exception of the heart failure result for amlodipine versus chlorthalidone, which did not differ significantly by gender. For both women and men, rates were not lower in the amlodipine or lisinopril groups than in the chlorthalidone group for either the primary coronary heart disease outcome or any other cardiovascular disease outcome, and chlorthalidone-based treatment resulted in the lowest risk of heart failure. Neither lisinopril nor amlodipine is superior to chlorthalidone for initial treatment of hypertension in either women or men.
PMCID: PMC4114223  PMID: 23529173
hypertension; gender; diuretic; calcium channel blocker; ACE inhibitor
3.  APOL1 Risk Variants, Race, and Progression of Chronic Kidney Disease 
The New England journal of medicine  2013;369(23):2183-2196.
Among patients in the United States with chronic kidney disease, black patients are at increased risk for end-stage renal disease, as compared with white patients.
In two studies, we examined the effects of variants in the gene encoding apolipoprotein L1 (APOL1) on the progression of chronic kidney disease. In the African American Study of Kidney Disease and Hypertension (AASK), we evaluated 693 black patients with chronic kidney disease attributed to hypertension. In the Chronic Renal Insufficiency Cohort (CRIC) study, we evaluated 2955 white patients and black patients with chronic kidney disease (46% of whom had diabetes) according to whether they had 2 copies of high-risk APOL1 variants (APOL1 high-risk group) or 0 or 1 copy (APOL1 low-risk group). In the AASK study, the primary outcome was a composite of end-stage renal disease or a doubling of the serum creatinine level. In the CRIC study, the primary outcomes were the slope in the estimated glomerular filtration rate (eGFR) and the composite of end-stage renal disease or a reduction of 50% in the eGFR from baseline.
In the AASK study, the primary outcome occurred in 58.1% of the patients in the APOL1 high-risk group and in 36.6% of those in the APOL1 low-risk group (hazard ratio in the high-risk group, 1.88; P<0.001). There was no interaction between APOL1 status and trial interventions or the presence of baseline proteinuria. In the CRIC study, black patients in the APOL1 high-risk group had a more rapid decline in the eGFR and a higher risk of the composite renal outcome than did white patients, among those with diabetes and those without diabetes (P<0.001 for all comparisons).
Renal risk variants in APOL1 were associated with the higher rates of end-stage renal disease and progression of chronic kidney disease that were observed in black patients as compared with white patients, regardless of diabetes status. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)
PMCID: PMC3969022  PMID: 24206458
Hypertension  2012;61(1):82-88.
The objective of our study was to determine the effects of two antihypertensive drug dose schedules (‘PM dose’ and ‘Add on dose’) on nocturnal blood pressure (BP) in comparison to usual therapy (‘AM dose’) in African Americans with hypertensive chronic kidney disease (CKD) and controlled office BP. In a three period, cross-over trial, former participants of the African American Study of Kidney Disease were assigned to receive the following three regimens, each lasting 6 weeks, presented in random order: AM dose (once daily antihypertensive medications taken in the morning), PM dose (once daily antihypertensives taken at bedtime) and ‘Add on dose’ (once daily antihypertensives taken in the morning and an additional antihypertensive medication before bedtime [diltiazem 60–120 mg, hydralazine 25 mg, or additional ramipril 5 mg]). Ambulatory BP monitoring was performed at the end of each period. The primary outcome was nocturnal systolic BP. Mean age of the study population (n=147) was 65.4 years, 64% were male, mean estimated GFR was 44.9 ml/min/1.73 m2. At the end of each period, mean (SE) nocturnal systolic BP was 125.6 (1.2) mm Hg in the AM dose, 123.9 (1.2) mm Hg in the PM dose, and 123.5(1.2) mm Hg in the Add-on dose. None of the pairwise differences in nocturnal, 24-hour and daytime systolic BP were statistically significant. Among African Americans with hypertensive CKD, neither PM (bedtime) dosing of once daily antihypertensive nor the addition of drugs taken at bedtime significantly reduced nocturnal BP compared to morning dosing of anti-hypertensive medications.
PMCID: PMC3523681  PMID: 23172931
Nocturnal blood pressure; chronic kidney disease; hypertension
5.  Long-term Effects of Renin-Angiotensin System–Blocking Therapy and a Low Blood Pressure Goal on Progression of Hypertensive Chronic Kidney Disease in African Americans 
Archives of internal medicine  2008;168(8):10.1001/archinte.168.8.832.
Antihypertensive drugs that block the renin-angiotensin system (angiotensin-converting enzyme inhibitors [ACEIs] or angiotensin receptor blockers) are recommended for patients with chronic kidney disease (CKD). A low blood pressure (BP) goal (BP, <130/80 mm Hg) is also recommended. The objective of this study was to determine the long-term effects of currently recommended BP therapy in 1094 African Americans with hypertensive CKD.
Multicenter cohort study following a randomized trial. Participants were 1094 African Americans with hypertensive renal disease (glomerular filtration rate, 20–65 mL/min/1.73 m2). Following a 3×2-factorial trial (1995–2001) that tested 3 drugs used as initial antihypertensive therapy (ACEIs, calcium channel blockers, and β-blockers) and 2 levels of BP control (usual and low), we conducted a cohort study (2002–2007) in which participants were treated with ACEIs to a BP lower than 130/80 mm Hg. The outcome measures were a composite of doubling of the serum creatinine level, end-stage renal disease, or death.
During each year of the cohort study, the annual use of an ACEI or an angiotensin receptor blocker ranged from 83.7% to 89.0% (vs 38.5% to 49.8% during the trial). The mean BP in the cohort study was 133/78 mm Hg (vs 136/82 mm Hg in the trial). Overall, 567 participants experienced the primary outcome; the 10-year cumulative incidence rate was 53.9%. Of 576 participants with at least 7 years of follow-up, 33.5% experienced a slow decline in kidney function (mean annual decline in the estimated glomerular filtration rate, <1 mL/min/1.73 m2).
Despite the benefits of renin-angiotensin system–blocking therapy on CKD progression, most African Americans with hypertensive CKD who are treated with currently recommended BP therapy continue to progress during the long term.
PMCID: PMC3870204  PMID: 18443258
6.  Intensive Blood-Pressure Control in Hypertensive Chronic Kidney Disease 
The New England journal of medicine  2010;363(10):918-929.
In observational studies, the relationship between blood pressure and end-stage renal disease (ESRD) is direct and progressive. The burden of hypertension-related chronic kidney disease and ESRD is especially high among black patients. Yet few trials have tested whether intensive blood-pressure control retards the progression of chronic kidney disease among black patients.
We randomly assigned 1094 black patients with hypertensive chronic kidney disease to receive either intensive or standard blood-pressure control. After completing the trial phase, patients were invited to enroll in a cohort phase in which the blood-pressure target was less than 130/80 mm Hg. The primary clinical outcome in the cohort phase was the progression of chronic kidney disease, which was defined as a doubling of the serum creatinine level, a diagnosis of ESRD, or death. Follow-up ranged from 8.8 to 12.2 years.
During the trial phase, the mean blood pressure was 130/78 mm Hg in the intensive-control group and 141/86 mm Hg in the standard-control group. During the cohort phase, corresponding mean blood pressures were 131/78 mm Hg and 134/78 mm Hg. In both phases, there was no significant between-group difference in the risk of the primary outcome (hazard ratio in the intensive-control group, 0.91; P = 0.27). However, the effects differed according to the baseline level of proteinuria (P = 0.02 for interaction), with a potential benefit in patients with a protein-to-creatinine ratio of more than 0.22 (hazard ratio, 0.73; P = 0.01).
In overall analyses, intensive blood-pressure control had no effect on kidney disease progression. However, there may be differential effects of intensive blood-pressure control in patients with and those without baseline proteinuria. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center on Minority Health and Health Disparities, and others.)
PMCID: PMC3662974  PMID: 20818902
7.  Longitudinal Progression Trajectory of GFR Among Patients With CKD 
The traditional paradigm of glomerular filtration rate (GFR) progression among chronic kidney disease (CKD) patients is a steady, nearly linear decline over time. We describe individual GFR progression trajectories over twelve years of follow-up among participants in the African American Study of Kidney Disease and Hypertension (AASK).
Study Design
Longitudinal, observational study
Setting & Participants
846 AASK patients with at least 3 years of follow-up and 8 GFR estimates.
Longitudinal GFR estimates (eGFR) from creatinine-based equations.
Patient demographic and clinical features.
Probability of a nonlinear trajectory and probability of a period of nonprogression, calculated for each patient from a Bayesian model of individual eGFR trajectories.
Three hundred and fifty-two (41.6%) patients exhibited a greater than 0.9 probability of having either a nonlinear trajectory or a prolonged nonprogression period; in 559 (66.1%), the probability was larger than 0.5. Baseline eGFR > 40 mL/min/1.73m2 and urine protein-creatinine < 0.22 g/g were associated with a higher likelihood of a nonprogression period. Seventy-four patients (8.7%) had both a substantial period of stable or increasing eGFR and a substantial period of rapid eGFR decline.
Clinical trial population; absence of direct GFR measurements.
In contrast to the traditional paradigm of steady GFR progression over time, many CKD patients have a non-linear GFR trajectory or a prolonged period of nonprogression. These findings highlight the possibility that stable kidney disease progression can accelerate, and, conversely provide hope that CKD need not be relentlessly progressive. These results should encourage researchers to identify time-dependent factors associated with periods of nonprogression and other desirable trajectories.
PMCID: PMC3312980  PMID: 22284441
Chronic kidney disease; estimated glomerular filtration rate; nonlinear progression; longitudinal cohort study; African American; slope
8.  Long-Term Effects of Incident Diabetes Mellitus on Cardiovascular Outcomes in People Treated for Hypertension 
Thiazide-type diuretics are associated with an increased incidence of diabetes as compared to other anti-hypertension medications. In this study we determined long-term cardiovascular disease (CVD) consequences of incident diuretic-associated diabetes compared to the effects of incident diabetes associated with calcium channel and ACE inhibitor use.
Methods and Results
22,418 participants from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial with baseline diabetes, incident diabetes (7.5% with chlorthalidone, 5.6% with amlodipine, and 4.3% with lisinopril), or no diabetes at 2 years of in-trial follow-up were followed for a mean total of 6.9 years (2.9 years in-trial and 4 additional years post-trial through the use of national data bases). The primary outcome was CVD mortality (death due to coronary heart disease [CHD], stroke, heart failure, or other CVD). Among other outcomes were all-cause mortality, non-CVD mortality, and CHD (nonfatal myocardial infarction/fatal CHD). Participants on chlorthalidone with incident diabetes versus no diabetes had consistently lower, non-significant risk for CVD mortality (hazard ratio [HR] 1.04, 95% confidence interval (CI 0.74–1.47), all-cause mortality (HR 1.04, 95% CI 0.82–1.30), and non-CVD mortality (HR 1.05, 95% CI 0.77–1.42) than participants with incident diabetes on amlodipine or lisinopril (HR’s 1.22–1.53). Participants with incident diabetes had elevated CHD risk compared to those with no diabetes (HR 1.46, 95% CI 1.09–1.96) but those on chlorthalidone had significantly lower risk than those on lisinopril (HR 1.18 versus 2.57, p for interaction = 0.04).
Our findings suggest that thiazide-related incident diabetes has less adverse long-term CVD impact than incident diabetes that develops on other antihypertensive medications.
PMCID: PMC3359874  PMID: 22396585
diabetes mellitus; diuretics; cardiovascular diseases; mortality; ALLHAT
9.  Mortality and Morbidity during and after the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial 
A randomized, double-blind, active-controlled, multicenter trial assigned 32,804 participants aged ≥55 years with hypertension and ≥1 other coronary heart disease risk factors, to receive chlorthalidone (n=15,002); amlodipine (n=8898); or lisinopril (n=8904) for 4 to 8 years, when double-blind therapy was discontinued. Passive surveillance continued for a total follow-up of 8 to 13 years, using national administrative databases to ascertain deaths and hospitalizations. During the post-trial period, fatal outcomes and nonfatal outcomes were available for 98% and 65% of participants, respectively, due to lack of access to administrative databases for the remainder. This paper assesses whether mortality and morbidity differences persisted or new differences developed over the extended follow-up. Primary outcome was cardiovascular mortality; secondary outcomes were mortality, stroke, coronary heart disease, heart failure, cardiovascular disease, and end-stage renal disease. For the post-trial period, data are not available on medications or blood pressure levels.
No significant differences (p < .05) appeared in cardiovascular mortality for amlodipine (HR 1.00 [0.93–1.06]) or lisinopril (HR 0.97 [0.90–1.03]), each compared to chlorthalidone. The only significant differences in secondary outcomes were for heart failure, higher for amlodipine (HR 1.12 [1.02–1.22]), and stroke mortality, higher for lisinopril (HR 1.20 [1.01–1.41]), each compared to chlorthalidone. Similar to the previously reported in-trial result, there was a significant treatment by race interaction for cardiovascular disease for lisinopril versus chlorthalidone; Blacks had higher risk than non-Blacks on lisinopril compared with chlorthalidone.. After accounting for multiple comparisons, none of these results were significant. These findings suggest that neither calcium channel blockers nor angiotensin converting-enzyme inhibitors are superior to diuretic in long-term prevention of major cardiovascular complications of hypertension.
PMCID: PMC3261592  PMID: 22235820
antihypertensive therapy; clinical trials; hypertension—general; pharmacologic (drug) therapy; clinical management of high blood pressure
10.  Metabolic Syndrome, Components, and Cardiovascular Disease Prevalence in Chronic Kidney Disease: Findings from the Chronic Renal Insufficiency Cohort (CRIC) Study 
American Journal of Nephrology  2011;33(6):477-484.
Metabolic syndrome may increase the risk for incident cardiovascular disease (CVD) and all-cause mortality in the general population. It is unclear whether, and to what degree, metabolic syndrome is associated with CVD in chronic kidney disease (CKD). We determined metabolic syndrome prevalence among individuals with a broad spectrum of kidney dysfunction, examining the role of the individual elements of metabolic syndrome and their relationship to prevalent CVD.
We evaluated four models to compare metabolic syndrome or its components to predict prevalent CVD using prevalence ratios in the Chronic Renal Insufficiency Cohort (CRIC) Study.
Among 3,939 CKD participants, the prevalence of metabolic syndrome was 65% and there was a significant association with prevalent CVD. Metabolic syndrome was more common in diabetics (87.5%) compared with non-diabetics (44.3%). Hypertension was the most prevalent component, and increased triglycerides the least prevalent. Using the bayesian information criterion, we found that the factors defining metabolic syndrome, considered as a single interval-scaled variable, was the best of four models of metabolic syndrome, both for CKD participants overall and for diabetics and non-diabetics separately.
The predictive value of this model for future CVD outcomes will subsequently be validated in longitudinal analyses.
PMCID: PMC3095834  PMID: 21525746
Cardiovascular disease; Chronic kidney disease; Chronic Renal Insufficiency Cohort (CRIC) Study; Metabolic syndrome
11.  Limitations of analyses based on achieved blood pressure: Lessons from the AASK trial 
Hypertension  2011;57(6):1061-1068.
Blood pressure (BP) guidelines that set target BP levels often rely on analyses of achieved BP from hypertension treatment trials. The objective of this paper was to compare the results of analyses of achieved BP to intention-to-treat analyses on renal disease progression. Participants (n=1,094) in the African-American Study of Kidney Disease and Hypertension Trial were randomized to either: (1) usual BP goal defined by a mean arterial pressure (MAP) goal of 102–107 mmHg or (2) lower BP goal defined by a MAP goal of ≤ 92 mmHg. Median follow-up was 3.7 years. Primary outcomes were rate of decline in measured glomerular filtration rate (GFR) and a composite of a decrease in GFR by > 50% or >25 ml/min/1.73m2, requirement for dialysis, transplantation, or death. Intention-to-treat analyses showed no evidence of a BP effect on either the rate of decline in GFR or the clinical composite outcome. In contrast, the achieved BP analyses showed that each 10 mm Hg increment in mean follow-up achieved MAP was associated with a 0.35 (95% CI 0.08 – 0.62, p = 0.01) ml/min/1.73m2 faster mean GFR decline and a 17% (95% CI 5% – 32%, p = 0.006) increased risk of the clinical composite outcome. Analyses based on achieved BP lead to markedly different inferences than traditional intention-to-treat analyses, due in part to confounding of achieved BP with co- morbidities, disease severity and adherence. Clinicians and policy makers should exercise caution when making treatment recommendations based on analyses relating outcomes to achieved BP.
PMCID: PMC3150108  PMID: 21555676
blood pressure control; African Americans; hypertension treatment; renal disease
13.  Central Pulse Pressure in Chronic Kidney Disease: A CRIC Ancillary Study 
Hypertension  2010;56(3):518-524.
Central pulse pressure can be non-invasively derived using the radial artery tonometric methods. Knowledge of central pressure profiles has predicted cardiovascular morbidity and mortality in several populations of patients, particularly those with known coronary artery disease and those receiving dialysis. Few data exist characterizing central pressure profiles in patients with mild-moderate chronic kidney disease who are not on dialysis. We measured central pulse pressure cross-sectionally in 2531 participants in the Chronic Renal Insufficiency Cohort study to determine correlates of the magnitude of central pulse pressure in the setting of chronic kidney disease. Tertiles of central pulse pressure (CPP) were < 36 mmHg, 36–51 mmHg and > 51 mmHg with an overall mean (± S.D.) of 46 ± 19 mmHg. Multivariable regression identified the following independent correlates of central pulse pressure: age, gender, diabetes mellitus, heart rate (negatively correlated), glycosylated hemoglobin, hemoglobin, glucose and PTH concentrations. Additional adjustment for brachial mean arterial pressure and brachial pulse pressure showed associations for age, gender, diabetes, weight and heart rate. Discrete intervals of brachial pulse pressure stratification showed substantial overlap within the associated central pulse pressure values. The large size of this unique chronic kidney disease cohort provides an ideal situation to study the role of brachial and central pressure measurements in kidney disease progression and cardiovascular disease incidence.
PMCID: PMC2941985  PMID: 20660819
Elasticity; epidemiology; diabetic nephropathies; hemodynamics; gender
14.  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
15.  Hypertension Awareness, Treatment, and Control in Adults With CKD: Results From the Chronic Renal Insufficiency Cohort (CRIC) Study 
A low rate of blood pressure control has been reported among patients with chronic kidney disease (CKD). These data were derived from population-based samples with a low rate of CKD awareness.
Study Design
Setting & Participants
Data from the baseline visit of the Chronic Renal Insufficiency Cohort (CRIC) study (n=3612) were analyzed. Participants with an estimated glomerular filtration rate of 20 to 70 ml/min/1.73m2 were identified from physician offices and review of laboratory databases.
Prevalence and awareness of hypertension, treatment patterns, control rates and factors associated with hypertension control.
Following a standardized protocol, blood pressure was measured three times by trained staff and hypertension was defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg and/or self-reported antihypertensive medication use. Patients’ awareness and treatment of hypertension were defined using self-report and two levels of hypertension control were evaluated: systolic/diastolic blood pressure <140/90 mmHg and <130/80 mmHg.
The prevalence of hypertension was 85.7%, and 98.9% of CRIC participants were aware of this diagnosis, 98.3% were treated with medications while 67.1% and 46.1% had their hypertension controlled to <140/90 mmHg and <130/80 mmHg, respectively. Of CRIC participants with hypertension, 15%, 25%, 26% and 32% were taking one, two, three and four or more antihypertensive medications, respectively. After multivariable adjustment, older patients, blacks, those with higher urinary albumin excretion were less likely while participants taking ACE-inhibitors and angiotensin receptor blockers were more likely to have controlled their hypertension to <140/90 mmHg and <130/80 mmHg.
Data were derived from a single study visit.
Despite almost universal hypertension awareness and treatment in this cohort of patients with CKD, rates of hypertension control were sub-optimal.
PMCID: PMC2866514  PMID: 19962808
16.  CYP3A4 and CYP3A5 Polymorphisms and Blood Pressure Response to Amlodipine among African-American Men and Women with Early Hypertensive Renal Disease 
American Journal of Nephrology  2009;31(2):95-103.
To explore the association between CYP3A4 and CYP3A5 gene polymorphisms and blood pressure response to amlodipine among participants from the African-American Study of Kidney Disease and Hypertension Trial randomized to amlodipine (n = 164).
Cox proportional hazards models were used to determine the risk of reaching a target mean arterial pressure (MAP) of ≤107 mm Hg by CYP3A4 (A–392G and T16090C) and CYP3A5 (A6986G) gene polymorphisms, stratified by MAP randomization group (low or usual) and controlling for other predictors for blood pressure response.
Women randomized to a usual MAP goal with an A allele at CYP3A4 A–392G were more likely to reach a target MAP of 107 mm Hg. The adjusted hazard ratio (AA/AG compared to GG) with 95% confidence interval was 3.41 (1.20–9.64; p = 0.020). Among participants randomized to a lower MAP goal, those with the C allele at CYP3A4 T16090C were more likely to reach target MAP: The adjusted hazard ratio was 2.04 (1.17–3.56; p = 0.010). After adjustment for multiple testing using a threshold significance level of p = 0.016, only the CYP3A4 T16090C SNP remained significant. CYP3A5 A6986G was not associated with blood pressure response.
Our findings suggest that blood pressure response to amlodipine among high-risk African-Americans appears to be determined by CYP3A4 genotypes, and sex specificity may be an important consideration. Clinical applications of CYP3A4 genotype testing for individualized treatment regimens warrant further study.
PMCID: PMC2853591  PMID: 19907160
Pharmacogenetics; Hypertension; Amlodipine; Renal failure; CYP3A polymorphisms; AASK; African-Americans
Blood pressure (BP) control rates and number of antihypertensive medications were compared (average follow-up 4.9 years) by randomized groups: chlorthalidone, 12.5-25 mg/d (n=15,255), amlodipine 2.5-10 mg/d (n=9,048), or lisinopril 10-40 mg/d (n=9,054) in a randomized double-blind hypertension trial. Participants were hypertensives age t55 with additional cardiovascular risk factor(s), recruited from 623 centers. Additional agents from other classes were added as needed to achieve BP control. BP was reduced from 145/83 mmHg (27% control) to 134/76 mmHg (chlorthalidone, 68% control), 135/75 mmHg (amlodipine, 66% control), and 136/76 mmHg (lisinopril, 61% control) by 5 years; the mean number of drugs prescribed was 1.9, 2.0, and 2.1, respectively. Only 28% (chlorthalidone), 24% (amlodipine), and 24% (lisinopril) were controlled on monotherapy. A majority achieved BP control in each randomized group--a greater proportion with chlorthalidone. Over time, providers and patients should expect multidrug therapy to achieve BP<140/90 mmHg in a majority of patients.
PMCID: PMC2897821  PMID: 19090876
Blood Pressure Control; Antihypertensive Agents; Randomized Controlled Trial
Archives of internal medicine  2009;169(9):832-842.
This paper re-evaluates the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) considering information from new clinical trials, meta-analyses, and recent ALLHAT analyses, especially those regarding heart failure and the association of drug treatment with new-onset diabetes (NOD) and its cardiovascular disease (CVD) consequences.
Subgroup and explanatory analyses from a long-term 4-arm double-blind randomized antihypertensive treatment trial in diverse North American settings.
Chlorthalidone was superior to 1) doxazosin in preventing combined CVD (CCVD) (RR=1.20, 95% CI 1.13-1.27), especially HF (RR=1.80, CI 1.40-2.22) and stroke (RR=1.26, CI 1.10-1.46); 2) lisinopril, in preventing CCVD (RR=1.10, CI 1.05-1.16), including stroke (in Black persons only) and HF (RR=1.20, CI 1.09-1.34); and 3) amlodipine, in preventing HF, overall (by 28%) and in hospitalized/fatal cases (by 26%). Central independent blinded re-review of HF hospitalizations confirmed each comparison. Results were consistent by age, sex, race (except for stroke and CCVD), diabetic status, metabolic syndrome status, and renal function level. Neither amlodipine nor lisinopril was superior to chlorthalidone in preventing end-stage renal disease overall, by diabetes status or by renal function level. In the chorthalidone arm, NOD was not significantly associated with CCVD (RR=0.96, CI 0.88-2.42).
Evidence from subsequent analyses of ALLHAT and other clinical outcome trials confirm that neither α-blockers, ACE-inhibitors nor calcium channel blockers surpass thiazide-type diuretics (at appropriate dosage) as initial therapy for reduction of cardiovascular or renal risk. Thiazides are superior in preventing heart failure, and new-onset diabetes associated with thiazides does not increase CVD outcomes.
PMCID: PMC2803011  PMID: 19433694
19.  Clinical Outcomes by Race in Hypertensive Patients with and without the Metabolic Syndrome in ALLHAT 
Archives of internal medicine  2008;168(2):207-217.
Antihypertensive drugs with favorable metabolic effects on glucose and lipid levels are advocated for first-line therapy in hypertensive patients with metabolic/cardiometabolic syndrome (MetS). We compared outcomes by race in black and nonblack hypertensive individuals with and without MetS treated with a thiazide-type diuretic (chlorthalidone), a calcium channel blocker (amlodipine besylate), an α-blocker (doxazosin mesylate), or an angiotensin-converting enzyme inhibitor (lisinopril).
A post hoc subgroup analysis from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), a randomized, double-blind, active-controlled hypertension treatment trial in 42 418 participants. We defined MetS as hypertension plus at least 2 of the following: fasting serum glucose level of at least 100 mg/dL, body mass index (calculated as weight in kilograms divided by height in meters squared) of at least 30 kg/m2, fasting triglyceride levels of at least 150 mg/dL, and high-density lipoprotein cholesterol levels of less than 40 mg/dL in men (or less than 50 mg/dL in women).
Significantly higher rates of heart failure were consistent across all treatment comparisons in those with MetS. Relative risks (RRs) were 1.50 (95% confidence interval [CI], 1.18–1.90), 1.49 (95% CI, 1.17–1.90), and 1.88 (95% CI, 1.42–2.47) in black participants and 1.25 (95% CI, 1.06–1.47), 1.20 (95% CI, 1.01–1.41), and 1.82 (95% CI, 1.51–2.19) in nonblack participants for amlodipine, lisinopril, and doxazosin comparisons with chlorthalidone, respectively. Higher rates for combined cardiovascular disease were observed with lisinopril-chlorthalidone (RR, 1.24 [95% CI, 1.09–1.40] and 1.10 [95% CI, 1.02–1.19], respectively) and doxazosin-chlorthalidone comparisons (RR, 1.37 [95% CI, 1.19–1.58] and 1.18 [95% CI, 1.08– 1.30], respectively), in black and nonblack participants with MetS. Higher rates of stroke were seen in black participants only (RR, 1.37 [95% CI, 1.07–1.76] for the lisinopril-chlorthalidone comparison; RR, 1.49 [95% CI, 1.09–2.03] for the doxazosin-chlorthalidone comparison). Black patients with MetS also had higher rates of end-stage renal disease (RR, 1.70 1 [95% CI, 1.13– 2.55]) with lisinopril compared with chlorthalidone.
The ALLHAT findings fail to do not support the preference of for calcium channel blockers, α-blockers, or angiotensin-converting enzyme inhibitors compared with thiazide-type diuretics in patients with the MetS, despite their more favorable metabolic profiles. This was particularly true for black participants.
PMCID: PMC2805022  PMID: 18227370
20.  Angiotensin-converting enzyme gene polymorphism predicts the time-course of blood pressure response to angiotensin converting enzyme inhibition in the AASK trial 
Journal of hypertension  2007;25(10):2082-2092.
It has yet to be determined whether genotyping at the angiotensin-converting enzyme (ACE) locus is predictive of blood pressure response to an ACE inhibitor.
Participants from the African American Study of Kidney Disease and Hypertension trial randomized to the ACE inhibitor ramipril (n = 347) were genotyped at three polymorphisms on ACE, just downstream from the ACE insertion/deletion polymorphism (Ins/Del): G12269A, C17888T, and G20037A. Time to reach target mean arterial pressure (≤ 107 mmHg) was analyzed by genotype and ACE haplotype using Kaplan–Meier survival curves and Cox proportional hazard models.
Individuals with a homozygous genotype at G12269A responded significantly faster than those with a heterozygous genotype; the adjusted (average number of medications and baseline mean arterial pressure) hazard ratio (homozygous compared to heterozygous genotype) was 1.86 (95% confidence limits 1.32–3.23; P < 0.001 for G12269A genotype). The adjusted hazard ratio for participants with homozygous ACE haplotypes compared to those heterozygous ACE haplotypes was 1.40 (1.13–1.75; P = 0.003 for haplotype). The ACE genotype effects were specific for ACE inhibition (i.e., not seen among those randomized to a calcium channel blocker), and were independent of population stratification.
African-Americans with a homozygous genotype at G12269A or homozygous ACE haplotypes responded to ramipril significantly faster than those with a heterozygous genotype or heterozygous haplotypes, suggesting that heterosis may be an important determinant of responsiveness to an ACE inhibitor. These associations may be a result of biological activity of this polymorphism, or of linkage disequilibrium with nearby variants such as the ACE Ins/Del, perhaps in the regulation of ACE splicing.
PMCID: PMC2792638  PMID: 17885551
angiotensin-converting enzyme; hypertension; polymorphisms; renal failure
21.  G-Protein-Coupled Receptor Kinase 4 Polymorphisms and Blood Pressure Response to Metoprolol Among African Americans: Sex-Specificity and Interactions 
American journal of hypertension  2009;22(3):332-338.
African Americans have a disproportionate burden of hypertension and comorbid disease. Pharmacogenetic markers of blood pressure response have yet to be defined clearly. This study explores the association between G-protein-coupled receptor kinase type 4 (GRK4) variants and blood pressure response to metoprolol among African Americans with early hypertensive nephrosclerosis.
Participants from the African American Study of Kidney Disease and Hypertension (AASK) trial were genotyped at three GRK4 polymorphisms: R65L, A142V, and A486V. A Cox proportional hazards model, stratified by gender, was used to determine the relationship between GRK4 variants and time to reach a mean arterial pressure (MAP) of 107 mm Hg, adjusted for other predictors of blood pressure response. Potential interactions between the three polymorphisms were explored by analyzing the effects of gene haplotypes and by stratifying the analysis by neighboring sites.
The hazard ratio with 95% confidence interval by A142V among men randomized to a usual MAP (102–107 mm Hg) was 1.54 (1.11–2.44; P = 0.0009). The hazard ratio by A142V with R65/L65 or L65/L65 was 2.14 (1.35–3.39; P = 0.001). Haplotype analyses were consistent but inconclusive. There was no association between A142V and blood pressure response among women.
Results suggest a sex-specific relationship between GRK4 A142V and blood pressure response among African-American men with early hypertensive nephrosclerosis. Men with a GRK4 A142 were less responsive to metoprolol if they had a GRK4 L65 variant. The effect of GRK4 variants and blood pressure response to metoprolol should be studied in larger clinical trials.
PMCID: PMC2715837  PMID: 19119263
22.  Design and Statistical Aspects of the African American Study of Kidney Disease and Hypertension (AASK) 
The African American Study of Kidney Disease and Hypertension (AASK) is a multicenter randomized clinical trial designed to test the effectiveness of three anti-hypertensive drug regimens and two levels of BP control on the progression of hypertensive kidney disease. Participants include African-American men and women aged 18 to 70 yr who have hypertensive kidney disease and GFR between 20 and 65 ml/min per 1.73 m2. The three anti-hypertensive drug regimens include an angiotensin converting enzyme inhibitor (ramipril), a dihydropyridine calcium channel blocker (amlodipine) or a beta-blocker (metoprolol) as initial therapy. The BP control levels are a lower goal (mean arterial pressure, ≤92 mmHg) and a usual goal (mean arterial pressure, 102 to 107 mmHg inclusive). The primary outcome is rate of change in renal function as measured by GFR, assessed by 125 I-iothalamate clearance. The main secondary patient outcome is a composite including the following events: (1) reduction in GFR by 50%, (2) end-stage renal disease, or (3) death.
PMCID: PMC1417393  PMID: 12819322
23.  Validation of Heart Failure Events in the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) Participants Assigned to Doxazosin and Chlorthalidone 
The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a randomized, double-blind, active-controlled trial designed to compare the rate of coronary heart disease events in high-risk hypertensive participants initially randomized to a diuretic (chlorthalidone) versus each of three alternative antihypertensive drugs: alpha-adrenergic blocker (doxazosin), ACE-inhibitor (lisinopril), and calcium-channel blocker (amlodipine). Combined cardiovascular disease risk was significantly increased in the doxazosin arm compared to the chlorthalidone arm (RR 1.25; 95% CI, 1.17–1.33; P < .001), with a doubling of heart failure (fatal, hospitalized, or non-hospitalized but treated) (RR 2.04; 95% CI, 1.79–2.32; P < .001). Questions about heart failure diagnostic criteria led to steps to validate these events further.
Methods and Results
Baseline characteristics (age, race, sex, blood pressure) did not differ significantly between treatment groups (P < .05) for participants with heart failure events. Post-event pharmacologic management was similar in both groups and generally conformed to accepted heart failure therapy. Central review of a small sample of cases showed high adherence to ALLHAT heart failure criteria. Of 105 participants with quantitative ejection fraction measurements provided, (67% by echocardiogram, 31% by catheterization), 29/46 (63%) from the chlorthalidone group and 41/59 (70%) from the doxazosin group were at or below 40%. Two-year heart failure case-fatalities (22% and 19% in the doxazosin and chlorthalidone groups, respectively) were as expected and did not differ significantly (RR 0.96; 95% CI, 0.67–1.38; P = 0.83).
Results of the validation process supported findings of increased heart failure in the ALLHAT doxazosin treatment arm compared to the chlorthalidone treatment arm.
PMCID: PMC149403  PMID: 12459039
heart failure; alpha-blocker; diuretic; clinical trial
24.  Treatment of Hypercholesterolemia in Black Patients 
The treatment of hypercholesterolemia in the black patient will be the next public health challenge facing physicians in the black community. Cost-effective care of hypercholesterolemia will be necessary and is possible, but it will require skill in the use of available therapies, extensive patient education, and excellent communication between patients and health care providers.
PMCID: PMC2625850  PMID: 3071613

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