The Prognositic Significance of Serial Renal Function Measurements in Chronic Heart Failure

Background: Impaired renal function is a strong prognostic factor in Chronic Heart Failure (CHF). Most studies of it, however, have assessed single measurements of renal function. Thus, the purpose of the present study was to determine the prognostic significance and importance of serial measurements of renal function before and after hospital discharge. Methods and results: A total of 542 consecutive patients admitted for worsening CHF (455 males, 60.6 ± 14.2 years) were studied. Estimated glomerular filtration rate (eGFR) was evaluated before discharge and 6 months later. Patients were followed-up to register cardiac death and rehospitalization due to worsening heart failure. We divided study subjects into four groups based on changes in renal function between before discharge and 6 months after. These were Group 1: normal to normal eGFR (≥60 mL/min/17.3m2), Group 2: reduced (<60 mL/min/17.3m2) to normal eGFR, Group 3: normal to reduced eGFR, and Group 4: reduced to reduced eGFR. Compared to Group 1, Groups 2, 3 and 4 had relative risks of 2.265-fold (P<0.05), 4.055-fold (P<0.001) and 3.974-fold (P<0.001), respectively, for adverse cardiac events after discharge. The multivariate Cox proportional hazard regression analysis demonstrated that log BNP at 6 months after discharge (hazard ratio [HR]: 1.768, P<0.001), peak VO2 (HR: 0.859, P<0.001) and eGFR <60 mL/min/1.73m2 at 6 months (HR: 1.854, P<0.05), but not eGFR at discharge, were independent predictors for cardiac events. Conclusion: Changes in renal function by serial measurements after discharge are important for the assessment of risk in CHF.