Comparison of Denosumab and Bisphosphonates for Sarcopenia in Postmenopausal Osteoporosis

Background: The objective of this study was to compare the effects of bisphosphonates and denosumab on sarcopenia-related parameters, contributing to a better understanding of osteosarcopenia management. Methods: This cross-sectional, comparative study assessed physical performance, muscle strength, muscle mass, and sarcopenia category in postmenopausal women aged 65 to 80 years with osteoporosis who were receiving either bisphosphonates or denosumab. Additional groups consisted of untreated osteoporotic patients and controls without osteoporosis (n = 50 per group). Muscle mass was assessed using bioelectrical impedance analysis, and the classification of sarcopenia was assessed according to the EWGSOP2 criteria. Results: Among the osteoporotic groups, the 4 m walking speed, 5-chair stand test, and timed up-and-go performance did not differ significantly, although denosumab-treated patients had numerically shorter completion times. Nondominant handgrip strength was the only grip parameter showing a significant between-group difference (p = 0.026), mainly due to higher values in denosumab-treated patients than in untreated osteoporotic patients; dominant and maximum handgrip strength were comparable. Skeletal muscle mass was higher in the denosumab group than in both the bisphosphonate-treated and untreated osteoporosis groups (p = 0.045), whereas ALM, ASM, and the ASMI did not differ significantly. No statistically significant between-group differences were observed in SARC-F scores or sarcopenia classifications. Controls had significantly higher odds of sarcopenia absence compared with untreated osteoporotic patients, and treatment duration was not correlated with sarcopenia-related parameters. Conclusions: These findings suggest a favorable but limited association between denosumab treatment and selected muscle-related parameters. Prospective longitudinal studies are needed to determine whether anti-osteoporotic therapies influence osteosarcopenia.