Effect of Oral Bisphosphonate Drug Holiday on Mortality Following Hip Fracture

Context Current clinical guidelines recommend a drug holiday after extended use of oral bisphosphonates. However, no studies have investigated the effect of drug holidays before hip fractures on postfracture mortality.Objective This work aimed to investigate the effect of a drug holiday on postfracture mortality in patients with extended use of oral bisphosphonates.Methods This retrospective, population-based cohort study took place among all patients with hip fractures in Victoria, Australia, from 2014 to 2018. Patients were adherent to oral alendronate or risedronate for 5 years or more prior to hip fracture. Group-based trajectory modeling categorized patients into different bisphosphonate usage after 5-year good adherence. The main outcome measure was postfracture mortality.Results We identified 365 patients with good adherence (medication possession ratio >= 80%) to oral alendronate/risedronate for 5 years or more. Most patients (69%) continued to use oral bisphosphonates until admission for hip fracture; 17% had discontinued for 1 year and 14% had discontinued for 2 years. Postfracture mortality was higher in patients who had discontinued risedronate for 1 year (hazard ratio [HR] 2.37; 95% CI, 1.24-4.53) and 2 years (HR 3.08; 95% CI, 1.48-6.41) prior to hip fracture. No increase or decrease in postfracture mortality was observed in patients who had discontinued alendronate for 1 year (HR 0.59; 95% CI, 0.29-1.18) or 2 years (HR 1.05; 95% CI, 0.57-1.93) prior to hip fracture.Conclusion Postfracture mortality is higher in people who discontinue risedronate, but not alendronate, for 1 or 2 years after being adherent to treatment for at least 5 years. The type of bisphosphonate may be a factor to consider when planning drug holidays.