Cystatin C and cardiovascular mortality in patients with coronary artery disease and normal or mildly reduced kidney function: results from the AtheroGene study.

AIMS Chronic kidney disease is associated with increased risk of cardiovascular disease. Cystatin C is a promising marker to reliably mirror renal function. The role of cystatin C in patients with coronary artery disease (CAD) and normal or mildly reduced kidney function is the subject of current investigation. METHODS AND RESULTS In 2162 patients, over the whole spectrum of CAD, baseline cystatin C concentrations were measured. Patients with an estimated glomerular filtration rate of < or =60 mL/min per 1.73 m(2) (n = 295) were excluded. In patients with complete follow-up information (n = 1827), 66 cardiovascular deaths were registered during a median follow-up of 3.65 years. Logarithmically transformed, standardized cystatin C was associated with cardiovascular death [hazard ratio: 1.94, 95% confidence interval (CI): 1.59-2.37, P < 0.001]. A potential threshold effect was observed; patients in the upper quartile had a 3.87-fold (95% CI: 2.33-6.42; P < 0.001) risk of mortality compared with the pooled lower quartiles. This risk association remained robust after adjustment for potential confounders including classical risk factors and N-terminal pro B-type natriuretic peptide. Serum creatinine was not associated with the outcome in this group of patients with normal renal function. CONCLUSION Results of this prospective study show that cystatin C is a potent predictor of cardiovascular mortality beyond classical risk factors in patients with CAD and normal or mildly reduced kidney function.