Denosumab and Mortality in a Real-World Setting: A Comparative Study

Denosumab (Dmab) is increasingly prescribed worldwide. Unlike bisphosphonates (BPs), its effect on mortality has yet to be well explored. This study examined the association between Dmab and all-cause mortality compared with no treatment in subjects with a fracture and BPs in subjects without a fracture. The study population was from the Sax Institute's 45 and Up Study (n = 267,357), a prospective population-based cohort with questionnaire data linked to hospital admissions (Admitted Patients Data Collection [APDC] data were linked by the Centre for Health Record Linkage), medication records (Pharmaceutical Benefits Scheme [PBS] provided by Services Australia), and stored securely (secure data access was provided through the Sax Institute's Secure Unified Research Environment [SURE]). The new-user cohort design with propensity-score (PS) matching was implemented. In the fracture cohort, Dmab and oral BP users were matched 1:2 to no treatment (Dmab: 617 women, 154 men; oral BPs: 615 women, 266 men). In the no-fracture cohort, Dmab users were matched 1:1 with oral BPs and zoledronic acid (Zol) users (Dmab:oral BPs: 479 men, 1534 women; Dmab:Zol: 280 men, 625 women). Mortality risk was measured using sex-specific pairwise multivariable Cox models. In the fracture cohort, compared with no treatment, Dmab was associated with 48% lower mortality in women (hazard ratio [HR] = 0.52, 95% confidence interval [CI] 0.36-0.72) but not in men. Oral BPs were associated with 44% lower mortality in both sexes (women HR = 0.56, 95% CI 0.42-0.77; men HR = 0.56, 95% CI 0.40-0.78). In the no-fracture cohort, compared with BPs, Dmab was associated with 1.5- to 2.5-fold higher mortality than oral BPs (women HR = 1.49, 95% CI 1.13-1.98; men HR = 2.74; 95% CI 1.82-4.11) but similar mortality to Zol. Dmab in women and oral BPs were associated with lower post-fracture mortality than no treatment. However, Dmab users had generally higher mortality than oral BP users in those without fractures. © 2023 American Society for Bone and Mineral Research (ASBMR).