Balance in children with chronic kidney disease: the relationship between skeletal muscle mass index, fatigue, and physical function

Background: The study evaluated the relationship between balance function and skeletal muscle mass index (ASMI), physical function, and fatigue in children with chronic kidney disease (CKD).

Methods: A cross-sectional study of 83 children with CKD (stages 1-4, dialysis, transplant) and 71 healthy controls was conducted. Functional performance tests, including gait speed, 6-min walk distance (6MWD), five-repetition sit-to-stand (5RST), and timed up-and-go (TUG) tests, were administered. Quadriceps muscle strength (QMS) and hand grip strength (HGS) were assessed alongside bioelectrical impedance analysis (BIA) for muscle mass evaluation. Fatigue was measured using the Child Fatigue Scale, and balance was assessed using the Pediatric Balance Scale. Multivariate linear regression, performed exclusively on the CKD cohort, was used to determine factors influencing balance.

Results: Children with CKD exhibited significantly lower muscle strength, physical performance, and balance than controls. Specifically, QMS on the right side was 7.16 ± 5.36 kg in the dialysis group versus 16.51 ± 8.66 kg in the CKD stages 1-4 group and 18.58 ± 7.27 kg in controls (p < 0.001). The 6MWD was 392 ± 50.34 m in the dialysis group compared to 476 ± 49.67 m in CKD stages 1-4 and 425 ± 68.94 m in controls (p < 0.001). Fatigue levels were highest in the dialysis group (41.00 ± 11.51), and balance scores were lowest in this group (47.71 ± 8.55) (p = 0.001 for both). Regression analysis showed that QMS (β = 0.333, p = 0.042), ASMI (β = 0.259, p = 0.043), gait speed (β = -0.347, p = 0.012), TUG (β = -0.656, p = 0.001), GFR (β = 0.238, p = 0.033), and lean mass (β = 0.710, p = 0.028) were significant predictors of balance.

Conclusions: The dialysis group presented the most significant reductions in ASMI, muscle strength, balance, and functional performance, alongside the highest fatigue levels. Balance was mainly influenced by fatigue, ASMI, QMS, and declining functional capabilities. Considering the negative impact of balance impairments on prognosis, early implementation of rehabilitation programs is essential for improving outcomes in CKD patients.