Retrospective Study of the Effects of Zoledronic Acid on Muscle Mass in Osteoporosis Patients

Several osteoporosis drugs can continuously improve bone mass, but the impact on muscle mass is still unknown. This study aims to investigate how zoledronic acid monotherapy affected muscle mass in osteoporosis patients. Patients from an osteoporosis database were divided into two groups in this retrospective cohort, case-control study: zoledronic acid-treated patients (n = 113) and a control group without osteoporosis treatment (n = 118). At four years, appendicular skeletal muscle mass (ASM) and appendicular skeletal muscle mass index (ASMI) were calculated using dual-energy X-ray absorptiometry. The differences in muscle mass between the groups were compared. At baseline, there was no difference in sex, ASM, ASMI, and bone mineral density between the zoledronic acid treatment group and the control group. The treatment group's skeletal muscle mass increased by 841 g in ASM and 0.35 kg/m in ASMI after three years, while decreased in the control group. This study for the first time demonstrated that that zoledronic acid is beneficial not only to the bone but also to muscle.