The effect of walk training with blood flow restriction in patients undergoing maintenance hemodialysis : a randomized controlled trial

Abstract

Background: Due to the decline in physical function, patients undergoing maintenance hemodialysis (MHD) may be unable to conduct moderate-to-vigorous exercise as recommended. Walk training (WT) with blood flow restriction (WT-BFR) could benefit various populations even at low-to-moderate exercise intensity. Yet, the evidence regarding the effects of WT-BFR in MHD patients is limited. This thesis aimed to explore the feasibility and effectiveness of WT-BFR in MHD patients. Methods: This thesis has three phases. Phase one is a meta-analysis to summarize the effectiveness of intradialytic exercise on the health-related quality of life (HRQOL) of MHD patients. Additionally, a network meta-analysis was performed to compare the effectiveness of various exercise types on physical function and HRQOL in MHD patients. Phase two is a cross-sectional survey to explore the availability of exercise programs, exercise habits, and HRQOL in MHD patients. Phase three is a randomized controlled trial (RCT). A total of 57 MHD patients (68.4% male) with a mean age of 53.6 years (SD = 10.4) were recruited and randomized into the WT-BFR (n = 19), WT (n = 19), and usual care (n = 19) groups. The WT group received 8-week, three sessions weekly, 20 minutes per session, and low-to-moderate intensity WT. The WT-BFR group received additional BFR during training based on the WT. The primary outcome is walking capacity, assessed by the 6-minute walk test (6MWT). The secondary outcomes include feasibility (i.e., attrition, adherence, safety, and participants’ perception), physical function (muscle strength, balance, and fall risk), HRQOL, anxiety, and depression. The feasibility was evaluated during all training sessions for the WT-BFR and WT groups, and other outcomes were assessed at baseline, post-intervention, and 8-week post-intervention for all participants. Results: The meta-analysis of 33 RCTs indicated that intradialytic exercise could benefit MHD patients by improving most generic and three disease-specific HRQOL domains. The network meta-analysis involving 90 RCTs demonstrated that intradialytic aerobic exercise with BFR ranked first for improving 6MWT, and intradialytic aerobic combined with resistance exercises was deemed optimal for MHD patients, as it could ameliorate various outcomes. The survey involved 827 MHD patients (61.9% male) with a mean age of 48.6 years (SD = 12.7) from 74 dialysis units, with fewer than one-fourth offering exercise programs. Significant correlations were found between exercise program availability and the regular exercise habits of MHD patients. Light exercise intensity and walking were identified as the primary characteristics of exercise among the participants. For the RCT, the overall dropout rate was 7.0%. Adherence to training sessions was 93.4% and 92.8% for the WT-BFR and WT groups, respectively. Participants reported a satisfactory perception of the interventions. No adverse events were reported. Analysis based on the intention-to-treat principle exhibited a significant group × time interaction effect in the WT-BFR and WT groups versus usual care for 6MWT after the intervention (mean difference and 95% confidence interval for WT-BFR: 48.48, 28.81 to 68.16, p < 0.001; WT: 31.70, 9.29 to 54.11, p = 0.006); as well as muscle strength, balance, fall risk, and three domains of HRQOL, but not for anxiety and depression. The WT-BFR group showed significant improvement over the WT group in lower limb muscle strength, balance, and the symptoms/problems list domain of HRQOL after the intervention, and 6MWT after an 8-week follow-up. Conclusions: This study is the first to investigate the feasibility and effectiveness of WT-BFR in MHD patients. The results indicate that WT-BFR is a feasible intervention for MHD patients. Both WT-BFR and WT surpassed usual care in improving 6MWT and other outcomes, with WT-BFR demonstrating a greater and more sustained impact in certain aspects. WT-BFR is suitable for MHD patients due to its low exercise intensity and high efficacy. The findings will provide comprehensive insights into WT-BFR and may aid in designing a more adaptable WT-BFR program tailored for MHD patients. (627 words)