Effects of denosumab and zoledronic acid on postmenopausal osteoporosis, bone density, and fat-free mass

Summary

This study compared denosumab and zoledronic acid for treating osteoporosis in drug-naïve postmenopausal Korean women. Over 3 years, both drugs significantly increased bone mineral density. However, denosumab also improved fat-free mass, suggesting it may be a better initial treatment for osteoporosis with low muscle mass, assuming all other conditions remain constant.

Background

Denosumab (DMAB) and zoledronic acid (ZOL), which are strong antiresorptive agents, are used to treat osteoporosis in postmenopause. Nonetheless, the data on their comparative efficacy in drug-naïve patients remain limited. Our research compared the therapeutic efficacy of DMAB and ZOL in drug-naïve postmenopausal Korean women with osteoporosis.

Methods

In total, 120 women were enrolled and equally divided to the DMAB and ZOL groups. The bone density and biochemical parameters of the patients were monitored over 3 years. Furthermore, the changes in fat-free mass (FFM), which comprises muscle mass, were assessed by bioelectric impedance analysis. Baseline characteristics, including age, BMI, and the prevalence of fractures, were similar between the groups at the onset of the study. Serum 25(OH), calcium and, phosphorus levels and baseline bone mineral density (BMD) were also comparable between the groups.

Results

Following 3 years of treatment, both groups exhibited a significant increase in BMD versus the baseline value. In particular, BMD increased by 9.7% and 5.1% at the lumber spine and total hip, respectively, in the DMAB group, versus increases of 7.1% and 4.4%, respectively, in the ZOL group. The increase in FFM was greater in the DMAB group. BMI-adjusted FFM decreased by 1.3% in the ZOL group, versus an increase of 3.6% in the DMAB group.

Conclusions

Conclusively, both DMAB and ZOL are effective antiresorptive agents that improved BMD over 3 years in drug-naïve individuals. Moreover, DMAB might represent a more reliable initial option for patients with osteoporosis accompanied by low muscle mass.