Timing of anti-osteoporosis medications initiation after a hip fracture affects the risk of subsequent fracture:​ a nationwide cohort study

Wang, Chen-Yu<sup>1,2,3,4</sup>; Fu, Shau-Huai<sup>5</sup>; Yang, Rong-Sen<sup>6</sup>; Chen, Liang-Kung<sup>7,8,9</sup>; Shen, Li-Jiuan<sup>1,2,10</sup>; Hsiao, Fei-Yuan<sup>1,2,10</sup>

Affiliations

¹School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan

²Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan

³Department of Education and Medical Research, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan

⁴Department of Pharmacy, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan

⁵Department of Orthopedics, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin County, Taiwan

⁶Department of Orthopedics, National Taiwan University Hospital, Taipei, Taiwan

⁷Aging and Health Research Center, National Yang Ming University, Taipei, Taiwan

⁸Department of Geriatric Medicine, National Yang Ming University School of Medicine, Taipei, Taiwan

⁹Center for Geriatrics and Gerontology, Taipei Veterans General Hospital, Taipei, Taiwan

¹⁰Department of Pharmacy, National Taiwan University Hospital, Taipei, Taiwan

Abstract and keywords

Objective: The optimal time after hip fracture to start prophylactic anti-osteoporosis medications (AOMs) remains uncertain, especially in real-world practice. Therefore, we investigated how timing of AOMs initiation affects the risk of subsequent osteoporotic fractures, and what factors influence timing of AOMs prescription.

Method: Patients ≥50 years old with diagnostic codes indicating hospitalization for hip fracture (n = 77,930) were identified from the Taiwan National Health Insurance Research Database; 9986 who were prescribed AOMs ≤1 year after a newly-diagnosed hip fracture were grouped into those who started AOMs from: ≤14 days (very early); 15–84 days (early); 85–252 days (late); and 253–365 days (very late). Associations with fracture-related hospitalizations after an index fracture were analyzed using a multivariate, time-dependent Cox proportional hazards model, and between-group differences compared by log-rank testing. Factors influencing timing of AOMs initiation were elucidated using multivariate logistic regression analyses.

Results: Compared to AOMs initiation from 15 to 84 days, initiation after 252 days was associated with significantly increased risk of fracture-related hospitalization (HR = 1.93, 95% CI 1.29–2.89). Both sensitivity and pre-specified subgroup analyses yield similar results. Among patients with high adherence to AOMs, the increased risk of subsequent fracture-related hospitalization among very late users was profound (HR = 2.56, 95% CI 1.41–4.64).

Conclusion: Timing of AOMs initiation was significantly associated with age, index year, index hospital length of stay as well as the accreditation level and geographic region of index hospital. After adjusting factors associated with timing of AOMs initiation and patients' adherence, the anti-fracture benefit of AOMs still depends crucially on the timely initiation of AOMs.

Keywords: Osteoporosis; Fracture prevention; Anti-osteoporosis medications; Health services research

Links

DOI: 10.1016/j.bone.2020.115452

PubMed: 32464276

WoS: 000557876000006

History

Received: 2019-10-16

Revised: 2020-05-22

Accepted: 2020-05-22

Online: 2020-05-25

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