Fluid overload trajectories and mortality in hemodialysis patients

BackgroundFluid overload remains critical in managing patients with end-stage kidney disease. However, there is limited empirical understanding of fluid overload's impact on mortality. This study analyzes fluid overload trajectories and their association with mortality in hemodialysis patients.Methods and patientsThis longitudinal study included 9332 incident hemodialysis patients from the EuCliD database, treated in Fresenius Medical Care NephroCare dialysis centers across seven countries between January 2016 and December 2019, with follow-up until May 2023. Fluid overload was assessed using bioimpedance spectroscopy, and patients were grouped based on fluid overload trajectories using group-based trajectory modeling. Cox regression models, adjusted for potential confounders, were used to investigate the relationship between trajectory groups and mortality.ResultsFour distinct fluid overload trajectories were identified. Patients in the highest trajectory group (8.5% of the cohort) had more frequent background cardiovascular complications, lower BMI and serum albumin, and their adjusted mortality risk was 2.20 times higher than the lowest trajectory. There was a dose-response relationship between trajectories and mortality. The incidence rate of death increased with the degree of fluid overload, from 8.6 deaths per 100 person-years in the lowest trajectory to 18.6 in the highest.ConclusionsThis longitudinal study highlights the significant risk of chronic fluid overload in hemodialysis patients. Latent trajectory analysis provides novel information into the dynamic nature of fluid overload and its impact on mortality in the hemodialysis population.