The effect of a 6-month intradialytic exercise program on hemodialysis adequacy and body composition: a randomized controlled trial

Abstract

Background/aim: End-stage kidney disease (ESKD) is strongly associated with factors that aggravate the physical activity level and body composition status of hemodialysis patients (HD). Even though exercise in HD patients have shown remarkable benefits on hemodialysis adequacy, it is yet inconclusive if exercise can positively affect body composition parameters or if dialysis adequacy may affect body composition status. This study aimed to investigate the effect of a 6-month intradialytic exercise training program on dialysis adequacy indices and body composition parameters in HD patients.

Study design: A total of 24 HD patients were randomly assigned into two equally sized groups. The exercise group (EX group) participated in a 6-month intradialytic moderate-intensity aerobic exercise training program at the beginning of the HD sessions, three times a week for 60 min, and maintained a Borg's Rating of Perceived Exertion score between 13 and 14. The Control group (C group) remained untrained. At baseline, during, and at the end of the 6-month study, we assessed single-pool Kt/V, urea reduction ratio (URR), and body composition parameters, such as extracellular water (ECW)/ intracellular water (ICW) ratio, body mass index (BMI) and lean tissue mass (LTM). In all patients, the 6-min-walking test (6MWT) was performed as a marker of physical performance.

Results: A significant increase of both Kt/V (increase by 19%, p = 0.01), and URR (increase by 7%, p = 0.03) values has been observed in the EX group after the 6-month training program. Similarly, a statistically significant increase in 6MWT distance (from 442 ± 67 m to 481 ± 68 m, p = 0.02) in the EX group has also been found, compared to the C group (from 393 ± 59 m to 427 ± 81 m, p = 0.06). Neither EX nor C group has shown significant changes in body composition parameters. After training, linear regression analysis revealed a strong positive correlation between Kt/V and 6MWT changes (r = 0.74, p = 0.04) in the EX group.

Conclusions: Six months of intradialytic aerobic exercise might increase dialysis adequacy, by increasing Kt/V and URR, and physical performance, regardless of changes in body composition indices.

Keywords: 6-Minute walking test; Body composition; Body composition adequacy; End-stage kidney disease; Intradialytic exercise.