Trajectories of oral bisphosphonate use after hip fractures: a population-based cohort study

Abstract

Summary: Bisphosphonates prevent future hip fractures. However, we found that one in six patients with hip fractures had a delay in bisphosphonate initiation and another one-sixth discontinued treatment within 12 months after discharge. Our results highlight the need to address hesitancy in treatment initiation and continuous monitoring. Purpose: Suboptimal antiresorptive use is not well understood. This study investigated trajectories of oral bisphosphonate use following first hip fractures and factors associated with different adherence and persistence trajectories. Methods: We conducted a retrospective study of all patients aged ≥ 50 years dispensed two or more bisphosphonate prescriptions following first hip fracture in Victoria, Australia, from 2012 to 2017. Twelve-month trajectories of bisphosphonate use were categorized using group-based trajectory modeling. Factors associated with different trajectories compared to the persistent adherence trajectory were assessed using multivariate multinomial logistic regression. Results: We identified four patterns of oral bisphosphonate use in 1811 patients: persistent adherence (66%); delayed dispensing (17%); early discontinuation (9%); and late discontinuation (9%). Pre-admission bisphosphonate use was associated with a lower risk of delayed dispensing in both sexes (relative risk [RR] 0.28, 95% confidence interval [CI] 0.21–0.39). Older patients (≥ 85 years old versus 50–64 years old, RR 0.38, 95% CI 0.22–0.64) had a lower risk of delayed dispensing. Males with anxiety (RR 9.80, 95% CI 2.24–42.9) and females with previous falls had increased risk of early discontinuation (RR 1.80, 95% CI 1.16–2.78). Conclusion: Two-thirds of patients demonstrated good adherence to oral bisphosphonates over 12 months following hip fracture. Efforts to further increase post-discharge antiresorptive use should be sex-specific and address possible persistent uncertainty around delaying treatment initiation.