Declining hip fracture rates in the United States.

To characterize the relationships between adherence (complance and persistence) to bisphosphonate therapy and risk of specific fracture types in postmenopausal women. Data were collected from 45 employers and 100 health plans in the continental United States from 2 claims databases during a 5-year period (January 1, 1999, through December 31, 2003). Claims from patients receiving a bisphosphonate prescription (alendronate or risedronate) were evaluated for 6 months before the Index prescription and during 24 months of follow-up to determine total, vertebral, and nonvertebral osteoporotic fractures, persistence (no gap in refills for >30 days during 24 months), and refill compliance (medication possession ratio > or = 0.80). The eligible cohort included 35,537 women (age, > or = 45 years) who received a bisphosphonate prescription. A subgroup with a specified diagnosis of postmenopausal osteoporosis was also evaluated. Forty-three percent were refill compliant, and 20% persisted with bisphosphonate therapy during the 24-month study period. Total, vertebral, nonvertebral, and hip fractures were significantly lower in refill-compliant and persistent patients, with relative risk reductions of 20% to 45%. The relationship between adherence and fracture risk remained significant after adjustment for baseline age, concomitant medications, and fracture history. There was a progressive relationship between refill compliance and fracture risk reduction, commencing at refill compliance rates of approximately 50% and becoming more pronounced at compliance rates of 75% and higher. Adherence to bisphosphonate therapy was associated with significantly fewer fractures at 24 months. Increasing refill compliance levels were associated with progressively lower fracture rates. These findings suggest that incremental changes in medication-taking habits could improve clinical outcomes of osteoporosis treatment.

Hip fractures among the elderly are a significant and rapidly growing public health problem. The prevailing view is that most hip fractures are the consequence of age-related bone loss or osteoporosis. However, because over 90% of hip fractures are the result of falls, we have undertaken a falls surveillance study to determine if factors related to the mechanics of falling are associated with increased risk of hip fracture. Case subjects with hip fracture and control subjects without hip fracture were sampled from falls recorded at the Hebrew Rehabilitation Center for Aged, a chronic care facility. Fall information was obtained by interview of the subject and witnesses if the fall was witnessed. Data were analyzed by multiple logistic regression. Increased risk of hip fracture from a fall was associated with impacting on the hip or side of the leg and potential energy associated with the fall. Quetelet, or body mass index, was inversely related to fracture risk. The adjusted odds ratio of hip fracture for a fall involving impact on the hip region was 21.7 (95% confidence interval, 8.2-58). The potential energy associated with these falls was an order of magnitude greater than the average energy required to fracture elderly, cadaveric, proximal femurs in earlier in vitro experiments. We conclude, therefore, that a fall from standing height should no longer be considered minimal trauma but rather trauma of sufficient magnitude to pose a high risk of hip fracture if impact occurs on the hip and if energy-absorbing processes are inadequate.(ABSTRACT TRUNCATED AT 250 WORDS)