Comparison of the efficacy between once-monthly oral ibandronate and risedronate among Korean women with osteoporosis: a nationwide population-based study.

ABSTRACT

Using a nationwide database from the Korean National Health Insurance Service, this study showed that once-monthly oral ibandronate (150 mg) had better anti-fracture efficacy than once-monthly oral risedronate (150 mg), as seen on assessing overall and non-vertebral fractures among Korean elderly women with osteoporosis. INTRODUCTION: Once-monthly oral bisphosphonates have been used widely without appropriate comparison. Therefore, we aimed to compare the anti-fracture efficacy of once-monthly ibandronate (150 mg) and once-monthly risedronate (150 mg). METHODS: We conducted a retrospective cohort study among Korean women aged ≥ 60 years from 2006 to 2015 using a nationwide database from the National Health Insurance Service Senior Cohort. The primary outcome was the first occurrence of fracture related to osteoporosis after the initial prescription of bisphosphonates. A Cox proportional model was used to estimate the incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for overall and site-specific fractures between the two treatments, after adjusting for possible confounding factors. RESULTS: After propensity score matching, the ibandronate and risedronate groups, with 3454 patients each, were assembled from 36,701 new once-monthly ibandronate or risedronate users. After 4 years of follow-up, the ibandronate group had significantly lower incidence rates of overall and non-vertebral fractures than the risedronate group (IRR 0.822, 95% CI 0.698-0.968, P = 0.919 and IRR 0.798, 95% CI 0.647-0.985, P = 0.036, respectively). CONCLUSIONS: Once-monthly ibandronate (150 mg) shows better anti-fracture efficacy than once-monthly risedronate (150 mg). However, further large-scale studies are required to confirm our findings and to determine site-specific differences, especially regarding the vertebral and hip areas.