Supplementary Material for: Body Mass Index Change and Hospitalization Risk in Elderly Hemodialysis Patients: Results from Japanese Dialysis Outcomes and Practice Patterns Study

Background: Short-term weight gains and losses are associated with a lower and higher mortality risk, respectively, in patients undergoing hemodialysis (HD). However, little is known about their association with the risk of subsequent hospitalization. Methods: In a prospective cohort of 1,804 HD patients aged ≥65 years enrolled in the Japanese Dialysis Outcomes and Practice Patterns Study phases 3 (2005–2008) and 4 (2009–2011), we examined the associations between changes in body mass index (BMI) over a 4-month baseline period (<–3%, –3 to <–1%, –1 to <1% [reference], 1 to <3%, and ≥3%) and subsequent risk of all-cause, cardiovascular, and noncardiovascular hospitalization using Cox models with adjustment for potential confounders. Results: During a median follow-up of 1.2 years, we noted 1,028 incident hospitalizations for any cause, including 275 and 753 hospitalizations for cardiovascular and noncardiovascular causes, respectively. An L-shaped association was observed between BMI change and all-cause hospitalization. The multivariable-adjusted hazard ratios (HRs; 95% CI) of all-cause hospitalization associated with BMI changes of <–3%, –3 to <–1%, 1 to <3%, and ≥3% (vs. –1 to <1%) were 1.29 (1.01–1.65), 1.22 (0.98–1.51), 1.04 (0.83–1.29), and 1.10 (0.83–1.45), respectively. Qualitatively similar associations were present for cardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.58 [1.06–2.37], 1.09 [0.75–1.58], 0.99 [0.72–1.36], and 0.91 [0.51–1.64], respectively) but not for noncardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.19 [0.90–1.57], 1.26 [0.99–1.59], 1.06 [0.84–1.35], and 1.18 [0.86–1.63], respectively). Conclusions: Decreases in BMI over a relatively short-term period were independently associated with higher risk of subsequent hospitalization, particularly cardiovascular-related hospitalization, among elderly HD patients.