Supplementary Material for: Mortality rates and a clinical predictive model for the elderly on maintenance hemodialysis: A large observational cohort study of 17,354 Asian patients

Background: Mortality following hemodialysis initiation may influence the decision to initiate hemodialysis in elderly patients. Our objective is to demonstrate mortality following hemodialysis initiation in elderly (≥70 years) and to derive a prediction risk score based on clinical and laboratory indicators to determine risk of all-cause mortality in patients aged ≥80 years.
Methods: We identified elderly (≥70 years) who initiated maintenance hemodialysis between January 2005 and December 2016 using data from the Thai Renal Replacement Therapy Registry. The mortality rate was determined based on age categories. A predictive risk score for all-cause mortality was created for 4,451 patients aged ≥80 years by using demographics, laboratory values, and interview-based parameters. Using a flexible parametric survival analysis, we predicted mortality 3, 6 months, 1, 5, and 10 years after hemodialysis initiation.
Results: 17,354 patients (≥70 years) were included, mean age 76.9±5.1 years, 46.5% male, and 6,309 (36.4%) died. Patient aged <80 years had a median survival time of 110.6 months. A 9-point risk score was developed to predict mortality in patients aged ≥80 years: age>85 years, male, body mass index<18.5 kg/m2, hemoglobin<10.0 g/dL, albumin<3.5 g/dL, substantial assistance required in daily living (1 point each), and Karnofsky Performance Score<50 (3 points). C-statistic of 0.797 indicated high model discrimination. Internal validation demonstrated good agreement between observed and anticipated mortality.
Conclusions: Hemodialysis is appropriate for patients aged 70–80 years. A risk score for mortality in patients aged ≥80 years has been developed. The score is based on seven readily obtainable and evaluable clinical characteristics.