Effect of alendronate on muscle mass: Investigation in patients with osteoporosis

Many osteoporosis drugs reliably increase bone mass in the elderly; if these drugs also had a positive effect on muscle, their benefit would be even greater. We examined the effect of alendronate monotherapy on muscle mass in patients with osteoporosis. In this retrospective cohort, case-control study, patients from an osteoporosis database were divided into 2 groups: alendronate-treated patients (group A; n = 199) and a control group receiving no drug treatment (group C; n = 233). Appendicular skeletal muscle mass (ASM) and skeletal muscle mass index (SMI) measured by dual-energy X-ray absorptiometry were assessed at approximately 1 year. The change in muscle mass was compared between the groups. At baseline, group A included more women and had lower height, weight, bone mineral content, and muscle mass than group C. A comparison of changes after 1 year—adjusted for age, sex, observation period, body mass index and initial values—revealed that the muscle mass in group A showed increases by 0.137 kg/m2 in SMI, 514 g in ASM, and 319 g in lower limb muscle mass (LLM). Group C showed no changes in muscle mass. A significant difference in the amount of change in ASM and LLM was found between the groups after adjustment: 2.5 times and 4.4 times higher, respectively, in groups A and C. However, the difference in SMI disappeared after adjustment. This is the first study to show that alendronate may have a positive effect not only on bone, but on muscle as well.