Medium Cut‐Off Versus High‐Flux Dialyzers and Changes in Beck Depression Inventory Scores in Maintenance Hemodialysis: An Exploratory Observational Study

INTRODUCTION: Depression is prevalent in maintenance hemodialysis patients and is influenced by the interplay of physical and mental health. Rather than a direct antidepressant effect of dialyzer membrane type, improved clearance of middle and large uremic solutes may alleviate uremia-related symptoms that indirectly influence mood and quality of life. METHODS: This prospective observational study compared changes in Beck Depression Inventory (BDI) scores over 6 months between thrice-weekly hemodialysis patients treated with Theranova-400 or FX80 dialyzers. RESULTS: Fifty participants were included (Theranova-400/FX80: 25/25; median age 52.5 [27.7] years; 27 females; dialysis vintage 60 [86] months). The reduction in BDI scores did not differ significantly between the two groups (p = 0.203). In the within-group analysis, a significant decline was observed in the FX80 arm (-4.72 ± 6.62, p = 0.003) but not in the Theranova-400 arm (-3.20 ± 10.3, p = 0.199). However, in the subgroup of patients with baseline BDI scores > 14, both dialyzer groups showed statistically significant decreases in BDI scores (FX80: 24.7 ± 7.3 to 16.5 ± 6.6, p = 0.016; Theranova-400: 24.1 ± 8.4 to 14.8 ± 10, p = 0.037). CONCLUSION: In this exploratory observational study, BDI scores decreased over 6 months in both groups; however, between-group change in BDI did not differ significantly. These findings do not support a dialyzer-specific antidepressant effect of Theranova-400 compared with FX80. Within-group changes, particularly in the FX80 arm, should be interpreted cautiously considering possible repeated-measurement effects, regression to the mean, and unmeasured confounding. Future studies should evaluate whether changes in uremic symptom burden mediate mood-related scores.