Kidney function is inversely associated with coronary artery calcification in men and women free of cardiovascular disease: The Framingham Heart Study

Background. Among patients with end-stage renal disease (ESRD), the risk of cardiovascular disease is 10 to 20 times higher than the general population. Adults with ESRD have increased coronary-artery calcification (CAC) detected by electron-beam computed tomography (EBCT). Because the risk of coronary heart disease is increased even at moderate declines in kidney function, we sought to test whether high CAC scores are seen among those with mild reductions in kidney function. Methods. Men and women free of symptomatic cardiovascular disease underwent EBCT. Coronary calcium was quantified using the method described by Agatston. Renal function was estimated by glomerular filtration rate (GFR). Spearman correlation coefficients were used to test the association between GFR and CAC. Results. Three hundred nineteen subjects (162 men/157 women), mean age 60, were included. Mean GFR was 86+/-23 mL/min/ 1.73 m(2) (range 31-169; 10% with GFR <60 mL/min/1.73 m(2)). The median CAC scores by quartile of GFR were 85.9, 48.1, 7.9, and 2.7. Overall, the unadjusted correlation of GFR and CAC was -0.28 (P<.0001). This remained significant after adjustment for age and sex (-0.11, P<0.05), and additionally after adjustment for body mass index (-0.11, P<0.05), hypertension (-0.11, P<0.05), or total cholesterol (-0.12, P=0.04). A similar correlation was noted after multivariable adjustment (-0.10, P<0.08). Conclusion. Mild declines in kidney function are associated with subclinical coronary artery calcification in a sample of subjects free of clinically apparent cardiovascular disease. This might help explain the increased risk of cardiovascular disease among individuals with renal dysfunction. Larger ongoing studies are needed to better quantify this finding.