Age-associated effects of intradialytic exercise on physical function and nutritional status in patients receiving ambulatory hemodialysis: A multicenter cohort study

Introduction: Intradialytic exercise is essential for improving physical function for older patients. This study aimed to examine the relationship between the effects of exercise therapy and aging.Methods: This multicenter cohort study included 1176 patients aged 40-89 years, who participated in an intradialytic exercise program, comprising stretching and resistance training, three times per week for 12 months. Isometric knee extension strength (IKES), 10-m walking speed, Short Physical Performance Battery (SPPB), and Geriatric Nutritional Risk Index (GNRI) were measured at baseline and after 12 months. The patients were divided according to age as follows: 40-59, 60-69, 70-79, and 80-89 years. A linear mixed-effects model examined the improvement within-group and between-control differences, as the 40-59 age group was the control group.Findings: The 40-59, 60-69, 70-79, and 80-89 age groups comprised 180, 317, 466, and 213 participants, respectively. Within-group differences, all the age groups significantly improved IKES and SPPB. The 10-m walking speed [0.02 (0.02) m/s] and GNRI [0.38 (0.33)] did not improved only in the 80-89 age group despite other age groups significantly improved. Between-control differences, IKES of the 70-79 age group [-0.24 (-0.42 to -0.06) %] was significantly lower improvement than control. GNRI of all the older groups were significantly smaller improvement than control (p < 0.05).Discussion: The older group demonstrated difficulty in improving walking ability and nutritional status compared with the younger groups. Clinicians need to consider the difference in effectiveness due to age and prescribe intradialytic exercises accordingly.