Mortality on Hemodiafiltration Compared to High-Flux Hemodialysis: A Brazilian Cohort Study

Abstract

Rationale & objective: Hemodiafiltration (HDF) has been associated with better survival than high-flux hemodialysis (HD), but these studies were mainly conducted in developed countries. This study examined the mortality risk among Brazilian patients with kidney failure, comparing treatment with HDF to treatment with high-flux HD.

Study design: Observational cohort study.

Setting & participants: All adult patients on maintenance dialysis (high-flux HD and HDF) at 29 dialysis facilities in Brazil between January 1, 2022 and December 31, 2023.

Exposure: Treatment with HDF patients versus high-flux HD.

Outcome: All-cause mortality and cause-specific mortality attributed to cardiovascular/cerebrovascular and infection-related diseases.

Analytical approach: Multivariable Cox proportional hazards regression in which dialysis modality was considered a time-updated exposure.

Results: The study included 8,391 patients: 6,787 receiving only high-flux HD, 2,836 receiving HDF, among whom 1,222 had migrated from high-flux HD to HDF during the follow-up period. The 2-year survival rates in these groups were 81.2% and 77.9%, respectively (P<0.001). A significantly lower adjusted death risk was observed among patients receiving HDF versus HD (HR, 0.73 [95% CI, 0.63-0.85]) in a time-updated analysis. HDF treatment was also associated with a reduction in cardiovascular mortality risk but not in infection-related death. In the subgroup analysis, the reduction in mortality risk associated with HDF was consistent across subgroups, with a more pronounced effect observed in patients under the age of 65 (HR, 0.56 [95% CI, 0.42-0.77]) than for those aged 65 or more (HR, 0.82 [95% CI, 0.70-0.96]). In a sensitivity analysis including only HD and HDF as starting therapy and data censored at the time of dialysis modality change, treatment with HDF was associated with a lower death risk (HR 0.73 [95% CI, 0.62-0.85]).

Limitations: The retrospective design and a relatively small follow-up period.

Conclusions: In this large cohort study conducted in Brazil, patients treated with HDF, compared with those treated with conventional high-flux HD, exhibited a lower risk of all-cause and cardiovascular mortality.

Plain-language summary: Hemodialysis (HD), after decades of dominance, has been challenged by online hemodiafiltration (HDF) as the new standard of therapy for kidney failure. HDF has been associated with better survival in recent clinical trials. However, data are scanty about its benefits in real-world studies with unselected dialysis populations. In this retrospective cohort study, we compared the mortality risk in patients treated with HDF (n=2,826) to the risk among those treated with high-flux HD (n=6,787) in Brazil. The 2-year survival rates in these groups were 81.2% and 77.9%, respectively (P<0.001). The adjusted all-cause mortality risk was 27% lower for patients treated with HDF compared with HD. HDF treatment was also associated with a 34% reduction in cardiovascular mortality risk.

Keywords: End-stage renal disease; hemodiafiltration; hemodialysis; mortality; survival.