Intradialytic Renal Rehabilitation and Mortality

KEY POINTS: Intradialytic renal rehabilitation was associated with higher 3-year survival in patients on maintenance hemodialysis. This association was directionally consistent after multivariable adjustment and propensity score matching. The association seemed stronger in men with severe frailty; no rehabilitation-related adverse events were reported. BACKGROUND: Frailty and sarcopenia are increasingly common among patients undergoing maintenance hemodialysis. Globally, some countries, including Japan, have recently introduced insurance reimbursement for intradialytic renal rehabilitation, a supervised intradialytic exercise instruction plus nutritional and lifestyle guidance. However, the survival benefit has not been fully evaluated. METHODS: We evaluated 708 adult outpatients on dialysis (age, 69.8±11.2 years; men, 59%; and Clinical Frailty Scale ≥6, 13%) at ten institutions across Japan in January 2021 who were retrospectively assessed over a 3-year period, including 228 patients who received intradialytic renal rehabilitation, defined as supervised intradialytic exercise instruction plus nutritional and lifestyle guidance (≥1 session/wk for≥1 month), and 480 who did not receive this intervention. Cox regression models and propensity score matching were used to compare 3-year mortality after adjustment for the Clinical Frailty Scale, comorbidities, laboratory data, and other baseline characteristics. RESULTS: During the follow-up, deaths were observed in 14.9% of the rehabilitation group and 23.1% of the nonrehabilitation group ( P = 0.01). Three-year survival was higher with rehabilitation (84.6% versus 75.6%, P = 0.007), particularly among men and those with severe frailty. In Cox models, renal rehabilitation was consistently associated with lower mortality (crude hazard ratio [HR], 0.59 [95% confidence interval (CI), 0.40 to 0.87]; adjusted HR 0.66 [0.44 to 1.00]). After propensity score matching, the association remained directionally similar (HR, 0.65 [0.40 to 1.05]). Sex-stratified analyses suggested a stronger association among men (adjusted HR, 0.49 [0.27 to 0.89]) than among women (adjusted HR, 0.98 [0.54 to 1.77]), although the formal test for interaction was not statistically significant ( P for interaction = 0.13). Patients meeting exercise-habit criteria (≥2 sessions/wk, ≥30 minutes for ≥1 year) also showed better survival relative to the nonexercise-habit group (adjusted HR 0.60 [0.37 to 0.96], P = 0.03). No adverse events related to rehabilitation were reported. CONCLUSIONS: Intradialytic renal rehabilitation may be associated with better survival in patients on maintenance hemodialysis, particularly in men and in those with severe frailty.