Age-stratified mortality and associated risk factors in adults aged 65 years or older undergoing continuous kidney...

As life expectancy increases and more adults aged ≥ 65 years undergo continuous kidney replacement therapy (CKRT), grouping patients into narrower age groups-rather than treating those aged ≥ 65 years as a single category-can provide more precise insights into age-related mortality risks.

This consecutive, retrospective study examined adults aged ≥ 65 years who underwent CKRT for acute kidney injury (AKI) at a tertiary hospital between August 2017 and March 2024. Participants were stratified into three age groups; 65-74 years, 75-84 years, and ≥ 85 years. The outcomes included 48-hour, 7-day, and in-hospital mortality. Logistic regression analysis was used to identify the impact of stratified age on mortality and the factors associated with age-specific mortality in each group.

Among the 1017 eligible patients, 292 (28.7%) died within 48 h, 402 (39.5%) within 7 days, and 607 (59.7%) during hospitalization. Compared with patients aged 65-74 years, those aged 75-84 years and those aged ≥ 85 years did not have an increased risk of 48-h, 7-day, or in-hospital mortality after adjustment for clinical variables. In patients aged 75-84 years, a higher serum albumin level was independently associated with lower in-hospital mortality (adjusted odds ratio [aOR], 0.35; 95% confidence interval [CI], 0.16-0.70; P = 0.004). In patients aged ≥ 85 years, a higher body mass index was significantly associated with reduced 7-day mortality (aOR, 0.74; 95% CI, 0.52-0.95; P = 0.037) and in-hospital mortality (aOR, 0.65; 95% CI, 0.43-0.87; P = 0.014).

In adults aged ≥ 65 years undergoing CKRT, advanced age was not associated with increased risk of early or in-hospital mortality. Among those aged ≥ 75 years, indicators of baseline health and nutrition status were associated with mortality. Age alone should not preclude CKRT decision-making in patients aged ≥ 65 years with AKI.