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 rate60 ml/min/1.73 m
