Functional impairment as predictors of renal outcomes and mortality in elderly patients: a retrospective cohort study

Functional impairments in elderly patients with chronic kidney disease may affect prognosis. This study evaluated the associations between activities of daily living (ADL), instrumental activities of daily living (IADL), renal replacement therapy (RRT), and mortality.

We retrospectively analyzed 6,087 adults aged ≥65 years (2,737 men and 3,350 women) who underwent geriatric assessment at Seoul National University Bundang Hospital from 2016 to 2020. All had an estimated glomerular filtration rate (eGFR) >15 mL/min/1.73 m2 and were followed for more than 3 months. ADL and IADL were measured using the Barthel and Lawton-Brody Index, and analyses were stratified by sex due to differences in IADL scoring criteria.

Participants (mean age, 78.7 ± 6.0 years; eGFR, 75.8 ± 19.4 mL/min/1.73 m2) were followed for a median of 42 months; 2,108 (34.6%) died and 103 (1.7%) initiated RRT. Impaired ADL and IADL were significantly associated with increased mortality in both sexes. In men, IADL impairment (<5) predicted RRT, whereas ADL (<100) showed a weaker association (p = 0.05). In women, neither ADL (<100) nor IADL (<8) significantly predicted RRT.

Functional impairments independently predicted mortality in both sexes and were associated with a higher risk of RRT in men, particularly among younger individuals or those with preserved renal function. ADL and IADL assessments may provide practical indicators for identifying high-risk elderly patients with early-stage kidney disease.