Metabolic Syndrome, Proteinuria, and the Risk of Progressive CKD in Hypertensive African Americans

Lea, Janice; Cheek, Deanna; Thornley-Brown, Denise; Appel, Lawrence; Agodoa, Lawrence; Contreras, Gabriel; Gassman, Jennifer; Lash, Jim; Miller, Edgar R.; Randall, Otelio; Wang, Xuelei; McClellan, William; AASK Study Investigators,

doi:10.1053/j.ajkd.2008.01.013

« Previous Next »American Journal of Kidney Diseases
Volume 51, Issue 5 , Pages 732-740, May 2008

Metabolic Syndrome, Proteinuria, and the Risk of Progressive CKD in Hypertensive African Americans

Janice Lea, MD, MSc
- Emory University, Atlanta, GA
- Address correspondence to Janice Lea, MD, Emory University, 101 Woodruff Circle, WMB Rm 338, Atlanta, GA 30322.
Deanna Cheek, MD
- Medical University of South Carolina, Charleston, SC
Denise Thornley-Brown, MD
- University of Alabama, Birmingham, AL
Lawrence Appel, MD
- Johns Hopkins University, Baltimore, MD
Lawrence Agodoa, MD
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
Gabriel Contreras, MD
- University of Miami, Coral Gables, FL
Jennifer Gassman, PhD
- Cleveland Clinic Foundation, Cleveland, OH
Jim Lash, MD
- University of Illinois, Chicago, IL
Edgar R. Miller III, MD, PhD
- Johns Hopkins University, Baltimore, MD
Otelio Randall, MD
- Howard University, Washington, DC.
Xuelei Wang, MS
- Cleveland Clinic Foundation, Cleveland, OH
William McClellan, MD, MPH
- Emory University, Atlanta, GA
AASK Study Investigators

Received 29 June 2007; accepted 17 January 2008. published online 25 March 2008.

Background

Chronic kidney disease (CKD) is more likely to progress to kidney failure (end-stage renal disease) in African Americans, although the reasons for this are unclear. Metabolic syndrome is a risk factor for the development of diabetes and cardiovascular disease and recently was linked to incident CKD. The purpose of this study is to examine whether metabolic syndrome is associated with kidney disease progression in hypertensive African Americans.

Design & Participants

The current study design is a secondary analysis of the African-American Study of Hypertension and Kidney Disease, a randomized controlled trial of blood pressure goal and agents in hypertensive African Americans with CKD.

Predictors

Metabolic syndrome was defined according to the modified National Cholesterol Education Program guidelines.

Outcomes

Decrease in glomerular filtration rate of 50% or 25 mL/min/1.73 m², end-stage renal disease (initiation of dialysis therapy or transplantation), death, or a composite outcome of all 3.

Results

842 subjects were included in this analysis, and 41.7% met criteria for metabolic syndrome. Subjects meeting criteria for metabolic syndrome had greater levels of proteinuria. Cox regression analyses adjusted for age, sex, glomerular filtration rate, and other significant covariates except for proteinuria indicated a 31% increased risk, with a 95% confidence interval of 1.03 to 1.7 (P = 0.03) for time to reach the composite outcome in those with metabolic syndrome. Adjusting for proteinuria, the effect was abated to 16% (95% confidence interval, 0.9 to 1.5), no longer remained significant (P = 0.2), and was unchanged by adjusting randomized treatment group (blood pressure goal or antihypertensive drug).

Limitations

Lack of waist circumference as a better surrogate of abdominal obesity.

Conclusions

In summary, metabolic syndrome is associated with proteinuria in hypertensive African Americans, but is not independently associated with CKD progression.

Index Words: Hypertension, African Americans, chronic kidney disease, metabolic syndrome