Prognostic significance of creatinine clearance rate in patients with heart failure and normal serum creatinine

Kidney failure is an important prognostic factor in patients with heart failure. Renal function is usually evaluated by measuring the serum creatinine level. However, a normal creatinine level can mask established kidney failure. We investigated the prognostic significance of the estimated creatinine clearance rate (Cockcroft formula) in 235 patients with heart failure and a normal serum creatinine level. The two-year mortality rate was significantly higher in patients who had established kidney disease (i.e., a creatinine clearance rate <60 mL/min) than in those who did not (35.1% vs. 10.1%, P<.001). Even when only patients without established kidney failure were analyzed, the creatinine clearance rate had prognostic significance (rate ≥ 90 mL/min, mortality 3.2%; rate 89-60 mL/min, mortality 13.9%; P=.02). On Cox regression analysis, which included age, sex, heart failure etiology, left ventricular ejection fraction, diabetes and hypertension, the creatinine clearance rate remained an independent predictor of mortality.