Waist-to-Hip Ratio and Body Mass Index as Risk Factors for Cardiovascular Events in CKD
Received 11 December 2007; accepted 4 April 2008. published online 03 June 2008.
Background
The role of obesity as a risk factor for cardiovascular disease in patients with chronic kidney disease (CKD) is poorly understood. Waist-to-hip ratio (WHR) is less influenced by muscle and bone mass than body mass index (BMI). We compared WHR and BMI as risk factors for cardiac events (myocardial infarction and fatal coronary disease) in persons with CKD.
Study Design
Cohort study.
Setting & Participants
Persons with CKD, defined as baseline estimated glomerular filtration rate of 15 to 60 mL/min/1.73 m2, drawn from 2 community studies: the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study.
Predictor
WHR, waist circumference, and BMI.
Outcomes & Measurements
Myocardial infarction and fatal coronary heart disease.
Results
Of 1,669 participants with CKD, mean age was 70.3 years and 56% were women. Mean (SD) WHRs were 0.97 ± 0.08 in men and 0.90 ± 0.07 in women; mean (SD) BMI was 27.2 ± 4.6 kg/m2. During a mean of 9.3 years of follow-up, there were 334 cardiac events. In multivariable-adjusted Cox models, the highest WHR group (n = 386) was associated with an increased risk of cardiac events compared with the lowest WHR group (hazard ratio, 1.36; 95% confidence interval, 1.01 to 1.83). Obesity, defined as BMI greater than 30 kg/m2 (n = 381), was not associated with cardiac events (hazard ratio, 0.86; 95% confidence interval, 0.62 to 1.20) in comparison to participants with normal BMI (<25 kg/m2). Results with waist circumference were similar to those with BMI.
Limitations
Absence of a gold standard for measurement of visceral fat.
Conclusions
WHR, but not BMI, is associated with cardiac events in persons with CKD. Relying exclusively on BMI may underestimate the importance of obesity as a cardiovascular disease risk factor in persons with CKD.
Because an author of this manuscript is an editor for AJKD, the peer-review and decision-making processes were handled entirely by an Associate Editor (Bryan Becker, MD, University of Wisconsin) who served as Acting Editor-in-Chief. Details of the journal's procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.
ABSTRACT