Renal insufficiency is a powerful predictor of worse outcome in patients with acute heart failure

Introduction

Large clinical trials have revealed that renal dysfunction (RD) is a common problem and one of the major negative predictors of survival in patients with acute heart failure (AHF); however, the influence of different degrees of RD on prognosis has been less well defined.

Methods

We studied 82 patients (mean age 69 ± 11 years, 64 male patients) admitted to our unit for AHF from July 2005 to November 2006. Fifty-eight percent of them (48 patients) met the criteria for RD. The aim of our study was to evaluate whether creatinine clearance (Cr-C) values calculated by Cockroft's formula [(140 - age (years)) × weight (kg)]/[72 × plasma creatinine level (mg/dl)] adjusted by sex correlated with inhospital mortality in this ICU population with AHF. We analyzed four subgroups of patients according their Cr-C: ≥ 90 ml/min, 89–60 ml/min, 59–30 ml/min and <30 ml/min. Kidney failure was defined as Cr-C < 60 ml/min. The etiology of AHF was mainly ischemic heart disease (68%) and mean the left ventricular ejection fraction was 31.6 ± 12.7%. We compared baseline characteristics and used a multivariable model to adjust and compare inhospital all-cause mortality across the Cr-C groups.

Results

Lower Cr-C was significantly related to older age, female gender, lower blood pressure and ischemic etiology. Cardiogenic shock was more frequent in patients with reduced Cr-C. Inhospital total mortality was significantly higher in RD patients than in those without RD (10% vs 3.3%), P < 0.0001. Mortality was 3.3% in patients with Cr-C ≥ 90 ml/min, 13.4% in patients with Cr-C between 89 and 60 ml/min, 24.2% in patients with Cr-C between 59 and 30 ml/min, and 62.5% in patients with Cr-C < 30 ml/min. OR = 3.2 (2.23–4.58), P < 0.001.

Conclusion

Among patients with AHF, RD is a frequent finding and a major risk factor for inhospital mortality. Even mild degrees of Cr-C impairment showed higher mortality rates than normal values.