Longer Hemodialysis Treatment Time Linked to Improved Survival in US Cohort

Key Clinical Summary

• A retrospective analysis of 146 127 US maintenance in-center hemodialysis patients found that longer dialysis treatment times were associated with lower all-cause mortality, fewer hospitalizations, and shorter hospital stays.
• Patients receiving 240 to 254 minutes of dialysis had a 27% lower mortality risk than those treated for 180 to 194 minutes, with benefits observed across a range of ultrafiltration volumes when spKt/V exceeded 1.4.
• Investigators suggest that extending treatment time may represent a practical strategy to improve outcomes, although findings are limited by the observational design and potential residual confounding.

The relationship between prescribed hemodialysis treatment time and clinical outcomes has remained controversial because treatment duration is closely tied to dialysis adequacy and ultrafiltration requirements. In a large retrospective study of patients receiving care at Fresenius Kidney Care clinics across the US, investigators found that longer dialysis sessions were consistently associated with improved survival and reduced hospitalization in a contemporary post-COVID cohort.

Longer Dialysis Sessions Associated With Lower Mortality

The study included 146 127 maintenance in-center hemodialysis patients aged 18 to 89 years who received treatment between January 1, 2022, and July 1, 2023. Patients were grouped according to their mean delivered dialysis treatment time, ranging from 180 to 269 minutes, and were followed for 1 year after a 30-day run-in period.

Compared with patients receiving 180 to 194 minutes of dialysis, those treated for 240 to 254 minutes experienced a 27% lower risk of all-cause mortality (hazard ratio [HR], 0.73; 95% CI, 0.69-0.76). Mortality was also lower among patients receiving 210 to 224 minutes and 225 to 239 minutes of treatment (HR, 0.81 for both groups), while treatment times of 195 to 209 minutes were associated with a 15% reduction in mortality.

The survival benefit remained consistent across patient subgroups with varying ultrafiltration volumes and among those achieving a single-pool Kt/V (spKt/V) greater than 1.4. However, patients with spKt/V of 1.4 or less did not experience similar improvements in mortality.

Secondary analyses demonstrated comparable trends for hospitalization outcomes. Longer treatment times, particularly those approaching 240 minutes, were associated with lower hospitalization rates and shorter hospital length of stay.

Investigators noted that patients receiving the longest treatment durations (255-269 minutes) did not experience additional reductions in mortality compared with the 240 to 254 minute group. This subgroup represented only 4% of the study population and differed in characteristics, including younger age, higher dry weight, and a greater proportion of patients with spKt/V below 1.4, which may have influenced the findings.

Clinical Relevance of Extending Hemodialysis Treatment Time

Despite advances in extracorporeal kidney replacement therapy, mortality among patients receiving maintenance in-center hemodialysis remains high. The findings suggest that extending treatment duration to approximately 240 to 254 minutes may offer a feasible and reproducible approach to improving survival while also reducing hospital utilization.

The investigators observed incremental reductions in mortality with each 15-minute increase in treatment time up to approximately 240 minutes. Benefits were consistent across sex and ultrafiltration volume categories and across most age groups, although patients older than 80 years did not demonstrate the same mortality advantage.

The authors emphasized that treatment times of at least 4 hours remain uncommon in the US despite their potential clinical value. They noted that both patient and provider reluctance, as well as operational challenges, may contribute to limited adoption of longer dialysis sessions. Given the difficulty of conducting another adequately powered randomized clinical trial, the investigators suggest that evidence from large observational cohorts may help inform future practice and support educational or operational strategies to overcome barriers to longer treatment times.

Expert Perspective Highlights Need for Practice Changes

The study authors concluded that their findings support reconsideration of dialysis treatment duration as a modifiable aspect of care. They stated that "our study findings of associations between longer treatment times and better patient survival, reduced hospitalization rates, and shorter hospital length of stay suggest a need to develop educational and/or operational interventions to overcome patient-, provider-, and facility-level barriers to extending hemodialysis treatment times."

The investigators also cautioned that the retrospective observational design cannot exclude selection bias or residual confounding, including potential effects of unmeasured factors such as residual kidney function and social determinants of health.

Longer hemodialysis treatment times were associated with improved survival, fewer hospitalizations, and shorter hospital stays in this large contemporary US cohort. Although causality cannot be established because of the observational study design, the findings support further efforts to evaluate and implement strategies that may facilitate longer dialysis sessions in appropriate patients.

Reference

Lasky R, Ficociello LH, Flythe JE, Hippen BE. The associations between dialysis treatment time, mortality, and hospitalizations in a large hemodialysis cohort. Kidney Int Rep. 2026;11(6):106483. doi:10.1016/j.ekir.2026.106483