Association of Intradialytic Exercise With Mortality and Hospitalization: A Cohort Study

Rationale & Objective Batients receiving hemodialysis have a markedly increased risk of mortality and hospitalization. While physical activity is associated with improved outcomes, the association between intradialytic exercise (IDE) and hard clinical endpoints remains poorly understood. This study analyzed the association between IDE dose and mortality and hospitalization. Study Design Multicenter prospective cohort study. Setting & Participants A total of 741 patients from 20 hemodialysis units were included. During the first year, participation in a routine clinical IDE program was monitored, and patients were subsequently followed for up to three additional years. Exposure Aerobic IDE dose (minutes/week). Patients were categorized as non-exercisers (n=394), low exercisers (<87 min/week; n=174), and high exercisers (≥87 min/week; n=173). Outcomes All-cause mortality, hospitalization risk, number of hospitalizations/year, and hospitalization days/year. Analytical Approach Cox proportional hazards models were used to analyze mortality and hospitalization risk. Quade's test compared hospitalizations/year and hospitalization days/year. Analyses were performed with and without adjustment for relevant covariates. Results During a median follow-up of 2.8 years, 129 patients (17.4%) died and 318 (42.9%) were hospitalized. Compared with non-exercisers, adjusted mortality risk was similar in the low-exercise group (p=0.603) but lower in the high-exercise group (HR, 0.35; 95% CI, 0.18–0.69; p=0.002). Among IDE participants, each 50-min/week increase in exercise dose was associated with lower mortality risk (HR, 0.46; 95% CI, 0.26–0.83; p=0.010). Adjusted hospitalization risk was not significantly reduced. However, the high-exercise group had fewer hospitalizations/year (p=0.021) and hospitalization days/year (p=0.028). Limitations Observational design, potential residual confounding and selection bias, and lack of information on physical activity outside dialysis. Conclusions Higher IDE volumes were associated with lower mortality and reduced hospitalization burden. However, many patients may not achieve an exercise dose sufficient to obtain these benefits. Therefore, strategies to increase exercise uptake and adherence and to complement IDE with alternative exercise interventions may help maximize clinical benefit.