Anti-Osteoporotic Therapy After Fragility Fracture Lowers Rate of Subsequent Fracture: Analysis of a Large Population Sample.

Background: This investigation assessed the effectiveness of initiating anti-osteoporotic therapy after a fragility fracture in preventing subsequent fractures.

Methods: The Truven Health MarketScan databases, which contain de-identified, integrated, person-specific claim data, were queried from 2003 to 2012. The study population included individuals fifty years of age or older who sustained a fragility fracture, defined as any fracture of the wrist, proximal part of the humerus, hip, or vertebra, and had three years of continuous enrollment following fracture. Patients were stratified into either an anti-osteoporotic therapy group or a no-treatment group. Subsequent fracture was defined as a fragility fracture occurring more than ninety days following the index fracture. Subjects were followed for three years. Unadjusted and age and sex-adjusted odds ratios for subsequent fracture were calculated for both groups.

Results: This investigation included 31,069 subjects, of whom 10.6% were treated with anti-osteoporotic therapy following the index fracture. The anti-osteoporotic therapy group was older and had a greater proportion of female patients compared with the no-treatment group. The three-year subsequent fracture rates were 7.5% in the anti-osteoporotic therapy group and 9.7% in the no-treatment group. Unadjusted odds ratios for subsequent fracture showed that the anti-osteoporotic therapy group experienced a risk reduction of 33% after an index wrist fracture, 48% after an index proximal humeral fracture, 28% after an index hip fracture, 20% after an index vertebral fracture, and 25% after all fractures combined. Age and sex-adjusted odds ratios showed that the anti-osteoporotic therapy group experienced a reduction in risk of 50% after an index wrist fracture, 52% after an index proximal humeral fracture, 34% after an index hip fracture, 43% after an index vertebral fracture, and 40% after all fractures combined. The number needed to treat to prevent a subsequent fragility fracture was twenty-eight after an index wrist fracture, twenty after an index proximal humeral fracture, twenty-six after an index hip fracture, twenty-five after an index vertebral fracture, and twenty-seven after all fractures combined.

Conclusions: Treatment with anti-osteoporotic therapy after a fragility fracture leads to a 40% decrease in the three-year risk of subsequent fracture, when adjusted for age and sex. Initiation of anti-osteoporotic therapy following a fragility fracture can prevent a subsequent fracture over the following three years in approximately one of every twenty-seven patients treated.