Comparative risk of fracture in community-dwelling older adults initiating suvorexant versus Z-drugs: Results from LIFE study

Abstract

Background: An increased risk of fracture has been reported in older adults taking hypnotics. However, few studies have reported the comparative safety of hypnotics with different mechanisms of action. We examined the risk of fracture in older adults initiating suvorexant compared to those initiating Z-drugs.

Methods: We conducted a retrospective cohort study using a claims database within a longevity improvement and fair evidence (LIFE) study in Japan (1.5 million beneficiaries). People aged ≥65 years were included in this study. Exposure was defined as the initiation of either suvorexant or Z-drugs (eszopiclone, zolpidem, or zopiclone). The evaluated outcomes were hip fracture and all-cause fracture requiring hospitalization. We used inverse probability of treatment weights to adjust for confounding and followed the incidence of the outcome for three different periods: 30, 90, and 365 days. Cox proportional hazards models were fitted to the weighted population to estimate hazard ratios (HRs). Sensitivity analyses were performed with narrowed outcome definitions and inverse probability of censoring weights.

Results: We identified 16,148 suvorexant new users and 54,327 Z-drugs new users. During the 30-day follow-up, 21 (16.6 events per 1000 person-years) and 53 hip fractures (12.2 events per 1000 person-years) were identified among suvorexant and Z-drugs new users, respectively (HR: 1.01, 95% confidence interval [CI]: 0.58-1.76). The analysis for all-cause fracture showed an HR of 1.03 (95% CI: 0.78-1.36). Extended follow-up (90 and 365 days) showed similar results for both outcomes. Sensitivity analyses showed consistent results except for an increased risk of all-cause fracture requiring surgery (HR: 1.41, 95% CI: 0.87-2.29) during the 30-day follow-up.

Conclusions: This is the first study to show that suvorexant has a generally comparable risk of fracture as compared to Z-drugs. Further research is needed to investigate the potential short-term increased risk of all-cause fracture requiring surgery among suvorexant initiators.

Keywords: comparative safety; fracture; hypnotics; older adults; real-world data.