24-month real-world persistence and compliance of denosumab versus alendronate among postmenopausal women with osteoporosis in Australia, Taiwan, South Korea, Hong Kong, and Singapore

INTRODUCTION: To compare 24-month persistence and compliance of denosumab with alendronate in postmenopausal women with osteoporosis across 5 Asia-Pacific territories. MATERIALS AND METHODS: This prospective cohort study included women aged ≥ 50 years from Australia, Taiwan, South Korea, Hong Kong, and Singapore. Participants received either a bi-annual denosumab injection or weekly oral alendronate as osteoporosis treatment, based on physician judgment. Multivariable logistic regression assessed whether therapy (denosumab or alendronate) was significantly associated with treatment persistence and compliance over 24 months of follow-up. The models were adjusted for age, fracture history, baseline bone mineral density (BMD), prior osteoporosis therapy, and prior oral glucocorticoid treatment. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. RESULTS: Among 687 enrolled patients, 549 completed their 24-month visit (295 in denosumab and 254 in alendronate group). Patients in the denosumab group were older and a higher proportion previously received osteoporosis treatment. Overall treatment persistence and compliance were 74.9% and 56.6%, respectively. Patients prescribed with denosumab exhibited higher persistence (86.1% vs. 61.8%; P < 0.001) and compliance (62.4% vs. 50.0%; P = 0.004), compared with those on alendronate. Regression results also demonstrated that patients receiving denosumab were more likely to be persistent (aOR = 3.91; 95% CI 2.52-6.08), and compliant (aOR = 1.61; 95% CI 1.12-2.31). BMD T-scores improved in both the treatment groups after 24 months with no significant association between treatment type and change in T-score. No significant difference was also observed in the occurrence of adverse events between the two treatment cohorts. Patients on alendronate reported gastrointestinal issues more frequently, whereas those on denosumab had a higher incidence of bone and joint injuries. CONCLUSION: Postmenopausal women with osteoporosis were more likely to be persistent and compliant with a bi-annual denosumab injection, compared with weekly oral alendronate.