Lower Hospitalization Rates During Fluid Management with Relative Blood Volume Monitoring: A Retrospective Cohort Analysis.

Background: Effective fluid management is critical for improving outcomes in patients undergoing chronic hemodialysis (HD). Relative blood volume monitoring (RBVM) supports the optimization of ultrafiltration rate adjustments; however, real-world evidence evaluating its impact on hospitalizations in chronic HD is limited. Methods: We conducted a retrospective, propensity score-matched observational cohort study comparing patient outcomes across 165 Fresenius Kidney Care clinics with high RBVM utilization (HI-RBVM; >90% of treatments) matched to 165 clinics not using RBVM (NO-RBVM). Data were collected from July to December 2022. Primary outcomes were patient-level all-cause and fluid-related hospitalizations and hospitalization days over a 6-month follow-up. Multivariable scaled Poisson regression models were used to estimate adjusted incidence rates, rate ratios, and rate differences. Secondary outcomes included patient-level changes in monthly clinical measurements. Results: 24,958 patients were included (11,840 across HI-RBVM clinics; 13,118 across NO-RBVM clinics). Adjusted incidence rates were lower in the HI-RBVM group compared to the NO-RBVM group for all-cause hospitalizations (1.57 vs. 1.70 per person-year [ppy]), fluid-related hospitalizations (0.30 vs. 0.35 ppy), and hospitalization days (9.60 vs. 10.8 ppy), corresponding to 119 fewer hospital days per 100 patient-years (95% CI: -184, -54; p < 0.001). Among patients with dialysis vintage ≤6 months, those treated in HI-RBVM clinics had smaller increases in pre-HD weight (-0.03 kg vs. +0.46 kg; p = 0.008) and ultrafiltration volume (0.11 L vs. 0.21 L; p = 0.004), and underwent more frequent estimated dry weight (EDW) adjustments (mean 7.73 vs. 6.61; p < 0.001). Conclusions: Among HD patients, high RBVM utilization at the clinic level was associated with lower rates of hospitalization. Prospective or quasi-experimental studies are needed to determine causality.