Prevalence and Associations of Coronary Artery Calcification in Patients With Stages 3 to 5 CKD Without Cardiovascular Disease

Background: Patients with chronic kidney disease (CKD) have a high prevalence of coronary artery calcification, suggesting that CKD itself is a risk factor for its occurrence. Existing studies are confounded by the inclusion of patients who may not have CKD by means of diagnostic criteria and by failing to account for existing cardiovascular disease. Study Design: Cross-sectional study. Participants & Setting: 119 patients with CKD stages 3 to 5 (excluding dialysis) without known cardiovascular disease receiving care at a single center in Kingston, Ontario, Canada. Predictors: Glomerular filtration rate was estimated (eGFR) by using the 4-variable Modification of Diet in Renal Disease Study equation. Traditional and nontraditional coronary artery calcification risk factors were defined a priori. Outcomes: Coronary artery calcification was measured by means of multislice computed tomographic scan. Results: Mean and median coronary artery calcification scores were 566.5 +/- 1,108 and 111 (interquartile range, 2 to 631.5), respectively. A total of 32.8% of patients showed little calcification (score, 0 to 10). Calcification correlated with age (r = 0.44; P < 0.001), body mass index (r = 0.28; P = 0.002), high-density lipoprotein cholesterol level (r = -0.23; P = 0.01), diabetes mellitus (r = 0.23; P = 0.01), and cardiovascular risk score (r = 0.35; P < 0.001). By means of multivariable linear regression controlling for eGFR and diabetes mellitus, age (beta = 0.05; 95% confidence interval, 0.03 to 0.06; P < 0.001), body mass index (beta = 0.04; 95% confidence interval, 0.02 to 0.07; P = 0.001), and serum calcium level (beta = 0.9; 95% confidence interval, 0.15 to 1.6; P = 0.02), were risk factors for coronary artery calcification. Limitations: Inadequate sample size and uncontrolled confounding are possible limitations, but are unlikely to have changed the main study findings. Conclusions: In this study, traditional cardiovascular disease risk factors and serum calcium level were associated with coronary artery calcification. No association was shown with eGFR. Studies exploring protective mechanisms against coronary artery calcification are needed. Am J Kidney Dis 52:849-858. (C) 2008 by the National Kidney Foundation, Inc.