Supplementary Material for: Intra-Dialytic Hemoglobin Changes and Cardiovascular Events: A Cohort Study on Dialysis Outcomes and Practice Patterns in Japan

Background: Ultrafiltration during hemodialysis (HD) causes hemoconcentration. Little is known about the relationships between intra-dialytic changes in hemoglobin concentration and cardiovascular events. Thus, this study aimed to elucidate the relationships between intra-dialytic changes in hemoglobin concentration and cardiovascular events among HD patients. Methods: This prospective cohort study was based on the Japanese Dialysis Outcomes and Practice Pattern Study phases 4 and 5. The predictor was the ratio of post-dialysis hemoglobin concentration to pre-dialysis hemoglobin concentration (post-Hb/pre-Hb) at baseline. The primary outcome was major adverse cardiovascular events (MACEs). Hazard ratios (HRs) were estimated using a Cox model for the association between post-Hb/pre-Hb and MACEs, adjusting for potential confounders. Results: A total of 865 patients were enrolled. During a median follow-up of 2.6 years, 145 (16.8%) patients developed MACEs. Patients were divided into 4 categories according to baseline post-Hb/pre-Hb (Conclusion: High and low intra-dialytic changes in hemoglobin concentration are associated with a high risk of MACEs in patients undergoing HD.