Abstract
Background: Following hip fracture, pharmacologic treatment can reduce the rate of subsequent fragility fractures. The objective of the present study was to assess the proportion of patients who are managed with bisphosphonates or selective estrogen-receptor modulators after hip fracture and to evaluate, among those managed with alendronate, the twelve-month compliance and persistence with treatment.
Methods: Data were gathered from health insurance companies and were collected by AIM (Agence Intermutualiste) for the Belgian National Social Security Institute (INAMI). We selected all postmenopausal women who had been hospitalized for a hip fracture between April 2001 and June 2004 and had not been previously managed with bisphosphonates. Patients who had received alendronate treatment after the hip fracture were categorized according to their formulation use during the follow-up study (daily, weekly, daily followed by weekly, or weekly followed by weekly). Compliance at twelve months was quantified with use of the medication possession ratio(i.e.,the number of days of alendronate supplied during the first year of treatment, divided by 365). Persistence with prescribed treatment was calculated as the number of days from the initial prescription to a lapse of more than five weeks after completion of the previous prescription refill. The cumulative treatment persistence rate was determined with use of Kaplan-Meier survival curves.
Results: A total of 23,146 patients who had sustained a hip fracture were identified. Of these patients, 6% received treatment during the study period: 4.6% received alendronate, 0.7% received risedronate, and 0.7% received raloxifene. Bisphosphonate treatment was dispensed to 2.6% and 3.6% of the patients within six months and one year after the occurrence of the hip fracture, respectively. Among women who received alendronate daily (n = 124) or weekly (n = 182) and were followed for at least one year after the hip fracture, the twelve-month mean medication possession ratio was 67% (65.9% in the daily group and 67.7% in the weekly group). The analysis of persistence with treatment included a total of 726 patients (142 in the daily group, 261 in the weekly group, and 323 in the switch group). At twelve months, the rate of persistence was 41% and the median duration of persistence was 40.3 weeks.
Conclusions: The vast majority of patients who experience a hip fracture do not take anti-osteoporotic therapy after the fracture. Furthermore, among patients who begin alendronate treatment after the fracture, the adherence to treatment decreases overtime and remains suboptimal.