Fracture-prevention benefits of anti-osteoporosis medications rely on timing

Timely initiation of anti-osteoporosis medications (AOMs), between 15 and 84 days after an index fracture, is crucial to obtaining their preventive benefit for subsequent fractures, a study has found.

Researchers looked at 77,930 individuals aged ≥50 years who had been hospitalized for hip fracture, among whom 9,986 were prescribed AOMs, including bisphosphonates, calcitonin, raloxifene, and denosumab, less than a year after being diagnosed with hip fracture.

AOM users were grouped according to the timing of medication initiation: ≤14 days (very early; n=1,826), 15–84 days (early; n=6,005); 85–252 days (late; n=1,746), and 253–365 days (very late; n=409). Early users were significantly older relative to other groups. Most very late users took AOMs concurrently with other medications. The very early group had the shortest length of hospital stay.

In multivariate Cox proportional hazards models, very late initiation of AOMs was associated with about a twofold higher risk of fracture-related hospitalization compared with early initiation (hazard ratio [HR], 1.93, 95 percent confidence interval [CI], 1.29–2.89).

The main AOMs used in this study was alendronate (68.74 percent), and the results of individual component of AOMs were similar with the overall cohort. Furthermore, both sensitivity and prespecified subgroup analyses yielded similar results.

The risk increase observed with very late AOM initiation was especially pronounced among patients with high medication adherence (HR, 2.56, 95 percent CI, 1.41–4.64).

The findings indicate that in addition to good adherence, early initiation of AOMs is important to effectively reduce the risk of subsequent fractures, the researchers said. They believe that the study contributes to current knowledge about the optimal time to initiate AOMs which can, in turn, be used to refine clinical practice.