PP185 - EXERCISE IS ASSOCIATED WITH MORE SYMMETRIC UREMIC TOXIN ELIMINATION IN HAEMODIALYSIS: AN EFFLUENT UV SENSOR ANALYSIS IN 1,046 SESSIONS

PP185

EXERCISE IS ASSOCIATED WITH MORE SYMMETRIC UREMIC TOXIN ELIMINATION IN HAEMODIALYSIS: AN EFFLUENT UV SENSOR ANALYSIS IN 1,046 SESSIONS

J. C. González Oliva^1,*, A. Roda Safont¹, V. Duarte Gallego¹, J. Ugalde Altamirano¹, K. Pasache Chong¹, A. Rovira Algara¹, V. Cazorla Rodríguez¹, J. Calls Ginesta¹, M. Mármol Guacalés¹

¹Nephrology, Hospital de Mollet, Mollet del Valles, Spain

Rationale: The temporal distribution of uremic toxin removal during haemodialysis may reflect treatment-specific metabolic patterns. Whether exercise modifies intra-session elimination asymmetry, and whether subdiffusion prevalence varies by albumin status, are unknown.

Methods: Retrospective observational study of 1,046 sessions in 61 patients (November 2025–April 2026): exercise (n = 223), non-exercise (n = 624), IDPN (n = 199). The Intra-session Asymmetry of Elimination index (IAE) and fractional diffusion exponent (alpha) were derived from the Nikkiso DDM 285 nm effluent UV signal. Handgrip, malnutrition inflammation score (MIS) and Short Physical Performance Battery (SPPB) were available in 48 patients. Spearman, Mann–Whitney and Kruskal–Wallis tests were used.

Results: IAE differed across groups (Kruskal–Wallis p = 0.010). Exercise sessions showed lower IAE (0.338 [0.303–0.428]) than non-exercise (0.369 [0.309–0.470]; d = 0.32; p = 0.002), indicating more symmetric elimination. IAE did not differ between IDPN and non-exercise (p = 0.25). Subdiffusion (alpha < 1) was present in 89.2% of sessions. Alpha was higher with albumin < 3.5 g/dL (0.630 vs 0.527; d = 0.29; p < 0.001), indicating greater diffusion anomaly with hypoalbuminaemia.

Conclusion: Intradialytic exercise is associated with more symmetric uremic toxin elimination compared with non-exercise, compatible with improved convective redistribution. Subdiffusion is highly prevalent across treatment types. Hypoalbuminaemia is associated with greater diffusion anomaly regardless of treatment modality.

Disclosure of Interest: None declared