Real-World Hospitalization Outcomes with On-Line Hemodiafiltration versus High-Flux Hemodialysis: A Retrospective, International Cohort Study

Background: Patients with end stage kidney disease undergoing hemodialysis (HD) experience high rates of hospitalizations and mortality, partly due to the incomplete removal of some toxic uremic molecules. To improve outcomes, multiple modalities of kidney replacement therapy have been developed, including high-flux HD and on-line hemodiafiltration (HDF). Notably, on-line high-volume HDF (HV-HDF) has demonstrated mortality benefits over high-flux HD in some randomized trials. Methods: This retrospective cohort study evaluated hospitalization outcomes among in-center dialysis patients treated with HV-HDF and high-flux HD at Fresenius Medical Care NephroCare centers across Europe, the Middle East, and Africa between January 2019 and December 2022. Data were extracted from the European Clinical Database. The primary outcome was all-cause hospitalization; secondary outcomes included cause-specific hospitalizations. Negative binomial regression was used to estimate incidence rate ratio (IRR) for hospital outcomes, incorporating inverse probability of treatment weighting (IPTW) to adjust for baseline differences between treatment groups. Results: A total of 71,669 patients were included, with 45% receiving HD and 55% receiving HDF. During the follow-up period, patients in the HDF group underwent a total of 12,741,453 HDF treatments, with a mean convection volume of 25.8L. Compared to HD, treatment with HDF was associated with a lower incidence of both hospital admissions (adjusted IRR, 0.80; 95% confidence interval [CI], 0.79−0.82) and days spent in the hospital (adjusted IRR, 0.80; 95% CI, 0.78−0.82). These reductions were consistent across subgroups analyzed and across most major causes of hospitalization, including cardiovascular disease, infections, and fluid-related complications. Conclusions: In this large, real-world cohort spanning multiple regions and dialysis centers, HV-HDF was associated with significantly lower rates of both hospital admissions and days spent in the hospital compared to treatment with high-flux HD. These findings suggest that HV-HDF may have the potential to reduce morbidity in patients with ESKD.