Mild and moderate pre-dialysis chronic kidney disease is associated with increased coronary artery calcium

BACKGROUND: It is increasingly evident that patients with chronic kidney disease (CKD) are more likely to die from heart disease than kidney failure. This study evaluated whether pre- dialysis CKD is an independent risk factor for coronary artery calcium (CAC). METHODS: A total of 544 consecutive patients who underwent CAC scoring were analyzed. Eleven patients requiring hemodialysis were excluded. Patients were divided into three groups: normal glomerular filtration rate (GFR) (GFR > 90 mL/min/1.73 m(2)), mild CKD (90 ≥ GFR > 60 mL/min/1.73 m(2)), and moderate CKD (60 ≥ GFR > 30 mL/min/1.73 m(2)). Continuous and categorical variables were compared using analysis of variance and the χ(2) statistic. A multiple logistic regression model was used for detecting the association between total CAC score and GFR. An unadjusted model was used, followed by a second model adjusted for covariates known to be related to CAC. Another multivariable binary logistic model predicting the presence of CAC (>10) was performed and odds of incidence of CAC (>10) were calculated among the three GFR subgroups. RESULTS: After adjustment for covariates, patients with mild CKD had mean CAC scores 175 points higher than those with the referent normal GFR (P = 0.048), while those with moderate CKD had mean CAC scores 693 points higher than the referent (P < 0.001). After adjustment for covariates, patients with mild CKD were found to be 2.2 times more likely (95% confidence interval 1.3–3.7, P = 0.004) and patients with moderate CKD were 6.4 times more likely (95% confidence interval 2.9–14.3, P < 0.001) to have incident CAC compared with the group with normal GFR. CONCLUSION: Mild and moderate pre-dialysis CKD are independent risk factors for increased mean and incident CAC.