Short- and long-term outcomes and 15-year time trends of kidney replacement therapy in critically ill patients with obesity: an observational cohort

Purpose Obesity is a public health challenge and a risk factor for chronic and acute kidney injury (AKI). The impact of kidney replacement therapy (KRT) on mortality in this specific population remains unclear. The objectives of this study were to evaluate the association between KRT and short- and long-term outcomes in patients with obesity, and to analyze trends over time in mortality as well as AKI and KRT incidence. Methods A retrospective analysis was conducted on all consecutive patients with obesity (body mass index >= 30 kg/m2) admitted to a medico-surgical intensive care unit from 2009 to 2024. AKI was defined using KDIGO criteria. The primary outcome was 90-day mortality assessed with Kaplan-Meier curves and multivariate Cox analysis. Secondary outcomes included 1-year mortality and time trends assessed on 90-day mortality, AKI, and KRT incidence, as well as SAPS II score. Results Among 2,192 patients with obesity included in the study, 295 (13.5%) required KRT. The 90-day mortality was significantly higher in the KRT group compared to the non-KRT group (49.8% (95% CI [44.1-55.5] vs. 18.9% (95% CI [17.2-20.7]), p < 0.0001). Multivariate analysis confirmed that KRT was independently associated with increased mortality. Over the 15-year period, AKI incidence decreased (p < 0.001). Conclusion Among critically ill obese patients, KRT was independently associated with increased 90-day mortality. These results highlight the need for prospective studies to better define optimal management strategies in this high-risk population.