Background: Impaired renal function confers an adverse prognosis in patients with heart failure (HF). The aims of the present study were to identify factors associated with and predictive of impaired renal function and to assess the relationship between estimated glomerular filtration rate (eGFR) and all-cause mortality in outpatients with HF.
Methods and results: Baseline data on 3605 patients (median age 73 years, 70.1% men) from 24 outpatient HF clinics in Norway were analyzed. Median follow-up time was 9 months. Renal dysfunction (eGFR < 60 mL/min) was present in 44.9%. The population was randomized into equal-sized model-building and validation samples to enhance model stability. eGFR was an independent predictor of all-cause mortality (HR 0.94 per 5 mL/min increase, P = .001). Use of spironolactone (P = .002), higher blood pressure (P < .001), and lower hemoglobin levels (P = .002) were predictors of impaired renal function. Increasing doses of loop diuretics were strongly associated with eGFR at baseline (P < .001), but only tended to predict worsening renal function during follow-up (P = .08).
Conclusions: Clinically significant reduction in renal function was prevalent in outpatients with HF, and was a strong predictor of all-cause mortality. Use of loop diuretics and spironolactone should be carefully evaluated as these agents may adversely affect renal function.