Study Overview
A 2026 study published in the Journal of Cachexia, Sarcopenia and Muscle compared the effects of denosumab and zoledronic acid on muscle strength and physical performance in postmenopausal women with osteoporosis. The research involved 186 participants, divided into two groups: 82 received denosumab, and 104 received zoledronic acid. Both treatments are used for osteoporosis, but their impact on muscle-related outcomes remained unclear. The study employed a prospective observational design, tracking participants over 36 months. Assessments included grip strength, gait speed, chair stand time, and imaging metrics like appendicular skeletal muscle mass index (ASMI), skeletal muscle volume index (SMVI), and muscle density. Biomarkers such as OPG/sRANKL ratios were also measured to explore biological mechanisms. The analysis used linear mixed-effects models for continuous outcomes and Fisher exact tests for categorical measures, with mediation analyses to evaluate potential pathways.
Key Findings
Denosumab demonstrated superior improvements in functional outcomes compared to zoledronic acid. By 12 months, grip strength increased by 1.45 kg (±0.51) in the denosumab group versus 0.66 kg (±0.34) in the zoledronic acid group. Gait speed improved by 0.041 m/s (±0.013) with denosumab versus 0.017 m/s (±0.011) with zoledronic acid. At 36 months, grip strength gains were 2.52 kg (±0.63) for denosumab versus 0.99 kg (±0.45) for zoledronic acid. Similar trends were observed in 5-times chair stand time and gait speed. Muscle mass metrics showed denosumab favoring greater increases in ASMI at 24 and 36 months. Sarcopenia prevalence was lower in the denosumab group at all time points (52.1% vs. 69.8% at 12 months, 30.2% vs. 50.7% at 24 months, 20.0% vs. 46.0% at 36 months). Denosumab also improved CT-derived muscle volume and reduced fat infiltration. OPG/sRANKL ratios increased more strongly with denosumab, and early biomarker changes correlated with later functional gains.
Limitations
The study’s observational design limits causal inferences, as randomization was not used. While the sample size was adequate for detecting differences, the cohort was restricted to postmenopausal women with prescreened sarcopenia risk, potentially limiting generalizability to broader populations. The 3-year follow-up period may not capture long-term effects or rare adverse events. Additionally, the study did not assess clinical outcomes like fractures or falls, focusing instead on surrogate markers. The authors noted the need for randomized controlled trials to confirm these findings and explore mechanisms of RANKL inhibition in osteosarcopenia. Biomarker analyses were secondary endpoints, requiring further validation in larger cohorts.
Conclusion
The study suggests that denosumab may offer greater short- and long-term benefits for muscle strength, physical performance, and sarcopenia reduction compared to zoledronic acid in postmenopausal women with osteoporosis. These findings align with the authors’ hypothesis that RANKL inhibition could address both bone and muscle health in osteosarcopenic phenotypes. However, the observational nature of the study and lack of clinical endpoints mean results should be interpreted cautiously. Further research is needed to confirm these associations and determine optimal treatment strategies for patients with combined osteoporosis and sarcopenia. The study highlights the importance of considering musculoskeletal outcomes beyond bone density when managing age-related degenerative conditions.
Unverifiable Claims
None. All claims are directly supported by the study’s results and methodology.