Positive association of vigorous and moderate physical activity volumes with skeletal muscle mass but not bone density or metabolism markers in hemodialysis patients.

Purpose: To determine whether vigorous and moderate physical activity volumes are associated with skeletal muscle loss and chronic kidney disease-mineral and bone disorder (CKD-MBD) in hemodialysis (HD) patients.

Methods: Skeletal muscle index (SMI) was measured using a bioelectrical impedance plethysmograph, and grip strength using a hand dynamometer, in 32 HD patients and 16 healthy controls. In HD patients, bone density was measured using digital image processing, and serum bone metabolism markers were measured as surrogate markers for CKD-MBD. Vigorous and moderate physical activity volumes of HD patients were measured using an activity monitor for 1 week, and associations between vigorous and moderate physical activity volumes and SMI, grip strength, and surrogate markers for CKD-MBD were investigated.

Results: SMI of HD patients (4.60 ± 0.98 kg/m(2)) was significantly lower than that of controls (5.55 ± 0.80 kg/m(2), p < 0.01). Grip strength of HD patients (19.9 ± 7.74 kg) was also significantly lower than that of controls (33.0 ± 8.94 kg, p < 0.01). In HD patients, vigorous and moderate physical activity volumes were significantly positively associated with SMI (β = 0.309, p = 0.023) but not grip strength (β = 0.231, p = 0131) after adjustment for age, sex, and HD duration. They were not associated with bone density (β = 0.106, p = 0.470) or any markers of bone metabolism.

Conclusions: Vigorous and moderate physical activity volumes were positively associated with skeletal muscle mass but not skeletal muscle strength or surrogate markers for CKD-MBD.