Two-year outcome and risk factors for mortality in patients with coronary artery disease and renal failure: The prospective, observational CAD-REF Registry

Background: Chronic kidney disease (CKD) and coronary artery disease (CAD) are strongly associated. CAD is the most frequent cause of cardiovascular death in patients with CKD.

Methods: The prospective observational nationwide multicenter Coronary Artery Disease and REnal Failure (CAD-REF) Registry enrolled 3352 patients with angiographically documented CAD classified according to their baseline estimated glomerular filtration rate (eGFR) into 5 groups according to the K/DOQI-guidelines. Patients were followed for two years. The aim of this study was the analysis of outcome and the identification of risk factors for two-year mortality in patients with both CKD and CAD.

Results: With decreasing renal function, patients had more often diabetes mellitus, hypertension, peripheral artery disease, and previous cardiovascular events and interventions. The amount of diseased vessels increased with decreasing renal function. For the whole cohort, two-year mortality was 6.5%. Kaplan-Meier-curves showed highest mortality in patients with CKD stages 4 and 5 (22.4%). In multivariate Cox-regression analyses, significant risk factors for two-year all-cause mortality were lower eGFR, current smoking, left ventricular ejection fraction, diabetes mellitus treated with oral medication or insulin, age, and peripheral artery disease. Coronary status missed the level of statistical significance as a risk factor for mortality in multivariable regression analysis. An eGFR reduction of 10ml/min/1.73m² increased the risk of mortality by 19% regardless of other risk factors.

Conclusions: Two-year morbidity and mortality increased with the degree of renal impairment. To improve survival of patients with CAD and CKD, nephroprotection is urgently needed especially for patients with atherosclerotic burden.

Clinical trial registration number: NCT00679419, http://clinicaltrials.gov/.