Denosumab and clinical outcomes among men with osteoporosis: a retrospective cohort study

Most subjects in osteoporosis clinical trials were women with postmenopausal osteoporosis and while bridging studies (BMD endpoint) provide an expectation that osteoporosis medications will reduce fracture risk in men. This real-world study shows direct evidence of fracture risk reduction among men with osteoporosis (36% of hip fracture reduction with denosumab).

Purpose: Direct evidence for fracture risk reduction of medications used among men with osteoporosis is very limited. This study aims to evaluate the real-world effectiveness of denosumab in reducing fracture risk.

Methods: This study included 13,797 men aged ≥ 50 years with osteoporosis who had initiated denosumab in Taiwan. Taiwan's National Health Insurance Research Database includes all Taiwan residents' complete health claim data. We compared incidence rates of clinical fractures between patients on denosumab 60 mg subcutaneously every 6 months (on-treatment) and patients ending therapy after one administration (off-treatment). Propensity score (PS) analysis, adjusting for measured differences at baseline covariates, was used to estimate the adjusted hazard ratio using a Cox proportion hazards model.

Results: During follow-up, 248 hip fracture events occurred. The crude incidence rates of hip fracture were 1.13 events and 1.73 events per 100 person-years in on-treatment and off-treatment cohorts, respectively. After PS inverse probability of treatment weighting, the cohorts achieved balance in all 59 covariates. The hip fracture event rate was lower in on-treatment cohort versus off-treatment cohort by 36% (hazard ratio, 0.64 [95% CI 0.50-0.83]). A similar magnitude of risk reduction was observed in clinical vertebral and nonvertebral fractures. A series of sensitivity analysis, including a validation analysis using a-million individual health records, demonstrated that unmeasured confounders were not suggested to impact study result interpretation.

Conclusion: In this large, real-world study evaluating denosumab treatment among men with osteoporosis, the observed fracture risk reductions were consistent with the available risk reductions demonstrated in clinical trials among women with postmenopausal osteoporosis.