Normal body mass index with central obesity has increased risk of coronary artery calcification in Korean patients with chronic kidney disease

Abstract

In chronic kidney disease (CKD), overweight and mild obesity have shown the lowest cardiovascular (CV) risk. However, central obesity has been directly associated with CV risk in these patients. This bidirectional relationship of body mass index (BMI) and central obesity prompted us to evaluate CV risk based on a combination of BMI and waist-to-hip ratio (WHR) in nondialysis CKD patients. We included 1078 patients with CKD stage 2 through 5 (nondialysis) enrolled in a nationwide prospective cohort of Korea. Patients were divided into 3 groups by BMI (normal BMI, 18.5-22.9; overweight, 23.0-27.4; and obese, 27.5 and over kg/m²) and were dichotomized by a sex-specific median WHR (0.92 in males and 0.88 in females). Coronary artery calcification (CAC) was determined by multislice computed tomography. CAC (score above 10 Agatston units) was found in 477 patients. Multivariate logistic regression analysis indicated that BMI was not independently associated with CAC. However, WHR showed an independent linear and significant association with CAC (odds ratio, 1.036; 95% confidence interval, 1.007-1.065 per 0.01 increase). Furthermore, when patients were categorized into 6 groups according to a combination of BMI and WHR, normal BMI but higher WHR had the highest risk of CAC compared with the normal BMI with lower WHR group (2.104; 1.074-4.121). Thus, a normal BMI with central obesity was associated with the highest risk of CAC, suggesting that considering BMI and WHR, 2 surrogates of obesity, can help to discriminate CV risk in Korean nondialysis CKD patients.

Trial registration: ClinicalTrials.gov NCT01630486.

Keywords: body mass index; cardiovascular disease; central obesity; chronic kidney disease; coronary artery calcification; waist-to-hip ratio.