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Article Title

Bisphosphonates Use and Risk of Hip Fractures

Publication Date

8-10-2017

Keywords

aging, elderly, geriatrics, observational studies, primary care, quality of care, clinical practice patterns/guidelines, clinical decision-making, chronic disease, risk adjustment, clinical outcomes, patient safety, epidemiology

Abstract

Background: Osteoporosis affects 200 million women worldwide, and fractures resulting from bone fragility are a major complication. Bisphosphonates slow down bone resorption by osteoclasts and have been shown to lower the risk of hip fractures among patients with osteoporosis in clinical trial settings. Most clinical guidelines recommend pharmacological treatment for postmenopausal women with an existing fracture or bone density T-score of -2.5 or lower. These guidelines were based on randomized controlled trials that typically lasted 3–4 years, although some of these studies have been extended for up to 10 years. We undertook this study to examine the association between adherence with bisphosphonate therapy and long-term risk of hip fracture, using up to 14 years of retrospective observation.

Methods: Included in the present nested case-control study were osteoporotic women (N = 14,357) who initiated bisphosphonate therapy between the years 2000 and 2010 and were retrospectively followed for incident hip fracture through November 2014. All cases of primary hip fracture within the cohort (n = 411) were individually matched with 411 controls based on age (± 1 year) and calendar year at therapy initiation as well as follow-up duration (± 1 year). For each study participant, the total dispensed packs of bisphosphonates during the follow-up period were counted.

Results: Compared to patients discontinuing therapy within 1 month, therapy with bisphosphonates for 1 to 3 years and 3 to 6 years was associated with adjusted odds ratios (and 95% confidence intervals) for hip fractures of 0.48 (0.27–0.86) and 0.40 (0.22–0.73), respectively. Comparable odds ratios were calculated for patients covered for longer periods –– 0.36 (0.17–0.76) for 6 to 8 years, and 0.57 (0.27–1.21) for 8 years or more.

Conclusion: Results suggest that 3 years or more of bisphosphonates use is associated with a substantially lower risk of primary hip fracture compared to nonpersistent patients. The results do not indicate further reduction in risk among patients treated for 8 years or more.

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