Different impact of chronic kidney disease in older patients with heart failure according to frailty

Background: Chronic kidney disease (CKD) and frailty are often present in older patients with heart failure (HF). Our aim was to evaluate the association of CKD and frailty in one-year mortality in a cohort of older (>= 75 years) outpatients with HF<br /> Methods: Our data come from the FRAGIC study ("impacto de la FRAGilidad y otros sindromes Geria<acute accent>tricos en el manejo clinico y prono<acute accent>stico del paciente anciano ambulatorio con Insuficiencia Cardiaca"), a multicenter prospective registry conducted in 16 cardiology services in Spain which included >= 75 years outpatients with HF. Renal function was assessed according to CKD-EPI formula. A comprehensive geriatric assessment was performed and frailty was identified according to visual mobility scale (frail if VMS >= 2). Survival rates were analyzed by Cox regression model.<br /> Results: We included 499 patients, mean age 81.4 +/- 4.3 years, 38 % women. Mean estimated glomerular filtration rate (eGFR) was 52.1 +/- 17.5 ml/min/1.72 m2. Patients were classified in normal renal function (eGFR >= 60 ml/min/1.72m2, 182 patients, 36 %), moderately impaired (eGFR 30-59 ml/min/1.72m2, 261 patients, 52.7 %) and severely impaired (eGFR<30 ml/min/1.72m2, 56 patients, 11.3 %). Patients with severe CKD were older, more often female, and presented a worse clinical profile, with higher comorbidity burden and frailty. After a median follow up of 371 days, 58 patients (11.6 %) died. Mortality was higher in patients with worse renal function (8.8 %, 11 % and 21 % according to renal function subgroups, respectively, p = 0.036) and frailty in the univariate analysis. However, only frailty, according to VMS, but not severe renal dysfunction, was independently associated with one year mortality.<br /> Conclusions: Most HF patients >= 75 years have renal dysfunction. CKD is a marker of worse prognosis in elderly patients with chronic HF, but it does not independently associate one-year mortality in the presence of frailty.