Prognostic value of reduced kidney function and anemia in patients with chronic heart failure.

Objectives: The present study aimed to evaluate the prognostic value of B-type natriuretic peptide (N-proBNP), renal dysfunction and anemia in chronic heart failure (CHF) patients. Methods: We analyzed data from a prospective cohort of 153 patients (mean age 64 years) with CHF referred to our hospital center. Clinical, echocardiographic and laboratory data were drawn during hospital recovery in all patients. Kidney dysfunction was defined as a glomerular filtration rate (GFR) < 60 ml/min and anemia as a hematocrit < 35%. After discharge, patients attended the outpatient clinic of our institution. Results: Kidney dysfunction was diagnosed in 37% of cases, whereas anemia was present in 25% of patients. During follow-up (median time 456 days), 32 patients died. Multivariate Cox proportional hazard model revealed that N-proBNP [hazard ratio (HR) = 1.002; P < 0.001] and GFR (HR = 0.972; P < 0.005) were significant predictors for mortality after adjustment for confounding variables. Kaplan-Maier analysis demonstrated a progressive decrease in survival from lowest to highest tertiles of N-proBNP values (log rank = 28.7; P < 0.001) and from higher to lower GFR values (log rank = 5.63; P < 0.01). Moreover, parametric survival analysis by the Weibull model demonstrated that the estimated probability of survival adjusted for N-proBNP values was higher in patients with GFR ≥ 60 ml/min than in those with GFR < 60 ml/min (P < 0.001). Conclusion: Increased N-proBNP and decreased kidney function, but not anemia, are independent risk factors for mortality in patients with CHF.