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 METHODS: Our data come from the FRAGIC study ("impacto de la FRAGilidad y otros síndromes Geriátricos en el manejo clínico y pronóstico del paciente anciano ambulatorio con Insuficiencia Cardíaca"), 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.

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.

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.