Purpose: Diabetes and osteoporosis occur frequently in older adults and are both associated with increased fracture risk. Denosumab treatment reduced new vertebral, nonvertebral, and hip fractures over 3 years, with continued low fracture incidence for up to 10 years in postmenopausal women with osteoporosis. However, its effects in diabetic subjects with osteoporosis have not yet been investigated.
Methods: Post hoc analysis of the 3-year, placebo-controlled FREEDOM study and 7-year Extension included postmenopausal women with osteoporosis and diabetes. Effects on BMD, vertebral, and nonvertebral fracture incidence were evaluated.
Results: Of 7808 subjects in FREEDOM, 508 with diabetes received denosumab (n = 266) or placebo (n = 242). Among those, BMD increased significantly with denosumab versus placebo in FREEDOM, and continued to increase during the Extension in long-term (continuing denosumab) and crossover (placebo to denosumab) denosumab subjects. In FREEDOM, denosumab-treated subjects with diabetes had significantly lower new vertebral fracture rates (1.6%) versus placebo (8.0%) (RR: 0.20 [95% CI 0.07–0.61]; p = .001). Nonvertebral fracture incidence was higher with denosumab (11.7%) versus placebo (5.9%) (HR: 1.94 [95% CI 1.00–3.77]; p = .046), although there were fewer hip fractures with denosumab (World Health Organization, 2017 ) than placebo (4; nonsignificant). During the first 3 years in FREEDOM Extension, new vertebral and nonvertebral fracture incidences were low in long-term and crossover denosumab diabetic groups (≤6%), consistent with the overall Extension population; yearly nonvertebral fracture incidence was comparable to the FREEDOM placebo group.
Conclusion: Denosumab significantly increased BMD and decreased vertebral fracture risk in subjects with osteoporosis and diabetes. No reduction in nonvertebral fractures was observed.