Clinical vulnerability and first-year mortality among patients undergoing unplanned hemodialysis initiation: a retrospective cohort study

Abstract Background Unplanned hemodialysis initiation is associated with poor outcomes and may occur in patients with greater clinical severity and inadequate predialysis preparation. However, the clinical profile and cumulative mortality during the first year among patients undergoing unplanned initiation remain incompletely characterized, particularly in contemporary Asian cohorts. This study aimed to characterize the clinical profile of patients undergoing unplanned hemodialysis initiation and to compare cumulative mortality during the first year between patients undergoing planned and unplanned initiation. Methods This retrospective cohort study included incident maintenance hemodialysis patients at Lampang Hospital, Thailand. Hemodialysis initiation was classified as planned or unplanned by medical record review using prespecified criteria. Unplanned initiation was defined as urgent or emergent initiation due to life-threatening complications or inadequate predialysis preparation. The primary outcome was 1-year all-cause mortality, with 90-day and 180-day mortality as secondary outcomes. An exploratory multivariable Cox model adjusted for age, diabetes mellitus, serum creatinine, and serum albumin. Results Among 233 incident hemodialysis patients, 135 underwent unplanned and 98 underwent planned initiation. Patients undergoing unplanned initiation had greater clinical and metabolic severity at baseline, including more frequent uremic symptoms, volume overload, respiratory failure, metabolic acidosis, and lower hemoglobin and serum albumin levels. During the first year, 26 deaths occurred. Cumulative mortality was higher in the unplanned group at 90 days (4.4% vs. 3.1%), 180 days (8.2% vs. 6.1%), and 1 year (14.8% vs. 6.1%). At 1 year, the unadjusted hazard ratio was 2.48 (95% CI 1.00–6.18). In an exploratory adjusted analysis, the hazard ratio for unplanned initiation was 2.93 (95% CI 1.11–7.72). Conclusions Patients undergoing unplanned hemodialysis initiation had greater clinical severity and predialysis vulnerability at baseline and experienced higher cumulative mortality during the first year. Given the substantial baseline differences, residual confounding, and limited number of deaths, these findings should be interpreted as identifying a clinically vulnerable population rather than demonstrating an effect attributable to unplanned initiation itself. Trial registration Not applicable. This was a retrospective cohort study.