Progressive Resistance Exercise Training in CKD: A Feasibility Study

Background: Skeletal muscle wasting in chronic kidney disease (CKD) is associated with morbidity and mortality. Resistance exercise results in muscle hypertrophy in the healthy population, but is underinvestigated in CKD. We aimed to determine the feasibility of delivering a supervised progressive resistance exercise program in CKD, with secondary aims to investigate effects on muscle size, strength, and physical functioning. Study Design: Parallel randomized controlled feasibility study. Setting & Participants: Patients with CKD stages 3b to 4 were randomly assigned to the exercise (n = 20; 11 men; median age, 63 [IQR, 57-65] years; median estimated glomerular filtration rate, 28.5 [IQR, 19.0-32.0] mL/min/1.73 m[superscript: 2]) or nonexercise control (n = 18; 14 men; median age, 66 [IQR, 45-79] years; estimated glomerular filtration rate, 20.5 [IQR, 16.0-26.0] mL/min/1.73 m[superscript: 2]) group. Intervention: Patients in the exercise group undertook an 8-week progressive resistance exercise program consisting of 3 sets of 10 to 12 leg extensions at 70% of estimated 1-repetition maximum thrice weekly. Patients in the control group continued with usual physical activity. Outcomes: Primary outcomes were related to study feasibility: eligibility, recruitment, retention, and adherence rates. Secondary outcomes were muscle anatomical cross-sectional area, muscle volume, pennation angle, knee extensor strength, and exercise capacity. Measurements Two- and 3-dimensional ultrasonography of skeletal muscle, dynamometry, and shuttle walk tests at baseline and 8 weeks. Results: Of 2,349 patients screened, 403 were identified as eligible and 38 enrolled in the study. 33 (87%) completed the study, and those in the exercise group attended 92% of training sessions. No changes were seen in controls for any parameter. Progressive resistance exercise increased muscle anatomical cross-sectional area, muscle volume, knee extensor strength, and exercise capacity. Limitations: No blinded assessors, magnetic resonance imaging not used to assess muscle mass, lack of a healthy control group. Conclusions: This type of exercise is well tolerated by patients with CKD and confers important clinical benefits; however, low recruitment rates suggest that a supervised outpatient-based program is not the most practical implementation strategy.