Renal Function and Exercise Training in AmbulatoryHeart Failure Patients With a Reduced Ejection Fraction

Patients with chronic kidney disease (CKD) and/or end-stage renal disease are less active and experience significant functional limitations. The impact of a structured aerobic exercise intervention on outcomes in ambulatory heart failure (HF) patients with comorbid CKD is unknown. HF-ACTION enrolled 2,331 outpatients with HF and a reduced ejection fraction (i.e., ≤35%) from April 2003 to February 2007 and randomized them to aerobic exercise training versus usual care. Patients were grouped according to the presence of CKD, defined as an estimated glomerular filtration rate <60 ml/min/1.73 m². A total of 2,091 patients (90%) had serum creatinine measured and were included in the final analytical cohort. The prevalence of CKD was 41% at baseline. In patients with and without CKD, respectively, the incidence of all-cause death and hospitalization was 75% and 63% over a median follow-up of 30 months. After adjusting for potential confounders, CKD was associated with increased risk of the composite of all-cause mortality and hospitalization (hazard ratio 1.18, 95% confidence interval 1.04 to 1.33; p value ≤0.01). With the exception of a marginally greater improvement in exercise duration in response to aerobic exercise training (estimate ± standard error: 0.9 ± 0.2 minutes vs 1.4 ± 0.1 minutes; p value = 0.01), there was no interaction between treatment arm and CKD on functional status, health-related quality of life, or clinical outcomes (p value ≥0.05 for all interactions). In conclusion, the prevalence of CKD was high in ambulatory reduced ejection fraction patients and was associated with a poorer overall prognosis but not a differential response to aerobic exercise training.