Total bilirubin as a mortality predictor in non-elderly hemodialysis patients: A multicenter retrospective cohort study

Background The association between serum total bilirubin (TBIL) levels and mortality in maintenance hemodialysis (MHD) patients, especially when stratified by age, has not been clearly established. Methods We performed a multicenter retrospective analysis of 409 MHD patients (40 deaths, 9.8%) over a median follow-up of 31.3 months (interquartile range (IQR), 28.9–31.8). Cox regression models evaluated TBIL’s predictive role for mortality. Receiver operating characteristic (ROC) curve-derived cutoff (8.79 µmol/L) stratified patients into high (H, TBIL > 8.79 µmol/L, n = 236) and low (L, TBIL ≤ 8.79 µmol/L, n = 173) groups. Multivariable Cox models adjusted for demographics, comorbidities (Model 2), and laboratory markers (Model 3). Kaplan-Meier analysis compared survival rates, with age subgroup comparisons. Results Significant differences emerged between H and L groups in hypertension history, platelet count, total protein, blood urea nitrogen, triglycerides, and total cholesterol (all P < 0.05). Adjusted models revealed elevated mortality risk in high TBIL patients (HR = 6.69, 95%CI 3.06–14.61, P < 0.01). Age-stratified analysis revealed dramatically elevated mortality risk in non-elderly high-TBIL patients (HR = 12.82, 95%CI 3.76–43.76, P < 0.001), but no significant association in elderly patients (HR = 2.00, 95%CI 0.83–4.81, P = 0.12). Conclusion TBIL independently predicts all-cause mortality specifically in non-elderly MHD patients, suggesting age-dependent clinical utility as a prognostic biomarker. Further studies should investigate unconjugated bilirubin fractions.