Effect of Synchronized Transcutaneous Electrical Diaphragm Stimulation Using Surged Faradic Current Combined With Inspiratory Muscle Training on Diaphragm Function and Clinical Outcomes in Patients With COPDEffect of Synchronized Transcutaneous Electrical Diaphragm Stimulation Using Surged Faradic Current Combined With Inspiratory Muscle Training on Diaphragm Function and Clinical Outcomes in Patients With COPDEffect of Synchronized Transcutaneous Electrical Diaphragm Stimulation Using Surged Faradic Current Combined With Inspiratory Muscle Training on Diaphragm Function and Clinical Outcomes

Chronic kidney disease (CKD) is a progressive condition that can be associated with reduced physical capacity, muscle weakness, fatigue, respiratory impairment and frailty. These problems may affect daily activities and quality of life. Exercise-based renal rehabilitation has been increasingly considered as an important part of the management of physical problems in CKD. However, evidence regarding multimodal rehabilitation in frail patients with CKD remains limited. Therefore, the present randomized controlled trial was conducted to evaluate the effect of a 12-week multimodal renal rehabilitation programme on pulmonary function, functional capacity and fatigue in patients with CKD who were classified as frail according to the Fried Frailty Phenotype. Frailty was defined by the presence of three or more of the five Fried criteria.

A total of 54 patients were screened, and 42 eligible participants were included and randomly allocated into two equal groups, with 21 participants in each group. Group A received the multidisciplinary renal rehabilitation, which included aerobic training, resistance training, inspiratory muscle training and multidisciplinary supportive care.

Group B received conventional physiotherapy along with standard medical care. The intervention was provided 3 times a week for 12 weeks. Pulmonary function was assessed using forced expiratory volume in one second, forced vital capacity and FEV₁/FVC ratio. Functional capacity was assessed using the 6-Minute Walk Test (6MWT) and the reported VO₂max measure. Fatigue was assessed using the Daily Fatigue Impact Scale. Assessments were performed before and after the intervention.

At baseline, there were no statistically significant differences between the two groups for pulmonary function, functional capacity or fatigue measures (p>0.05), indicating that the groups were comparable before the intervention. Following the 12-week intervention, significant improvements were observed within Group A for FEV₁, FVC, FEV₁/FVC ratio, 6MWD, VO₂max and D-FIS (p<0.001 for all outcomes). Significant within-group improvements were also observed in Group B for the measured pulmonary function, functional capacity and fatigue outcomes (p<0.001).

The between-group analysis showed statistically significant differences in favour of Group A for FEV₁, FVC, 6MWD, VO₂max and D-FIS (p<0.001). However, the between-group difference in FEV₁/FVC ratio was not statistically significant (p>0.05).

Thus, although both groups demonstrated improvement over time, the multimodal renal rehabilitation group demonstrated significantly greater improvement in most of the measured outcomes compared with conventional physiotherapy along with standard medical care.

The findings suggested that the multidisciplinary renal rehabilitation was effective in

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improving pulmonary function, functional capacity and fatigue in CKD patients with frailty over the 12-week intervention period. The improvement in fatigue was particularly evident from the significant reduction in D-FIS scores in Group A compared with Group B (between-group p<0.001). Similarly, the significant between group improvement in 6MWD and VO₂max (p<0.001) indicated better functional exercise capacity following the rehabilitation programme. The findings were consistent with previous research showing beneficial effects of exercise-based interventions on physical function and fatigue in patients with CKD. However, the study evaluated a combined rehabilitation programme, and therefore the individual contribution of aerobic training, resistance training, inspiratory muscle training and multidisciplinary support could not be determined separately. Other limitations included the relatively small sample size, and limited follow-up period.

Therefore, larger randomized controlled trials with longer follow-up are required to confirm the findings and determine whether the observed improvements are observed over time. Overall, the study concluded that a 12-week multidisciplinary renal rehabilitation may be a useful approach for improving pulmonary function, functional capacity and fatigue in CKD patients with frailty.