Hip fracture rates and bisphosphonate consumption in Spain. An ecologic study

Bisphosphonates are used worldwide to treat osteoporosis and, thus, to prevent fractures. Though they have been proven in clinical trials to avoid some fractures, their effectiveness in reducing hip fractures is unclear. The aim of the present study was to explore the relationship between bisphosphonate use and hip fracture trends in Spain.

For this purpose, an ecologic study spanning 2002 to 2008 was conducted in Spain. Consumption data were obtained from the Spanish Ministry of Health and Social Policy. The number of hip fractures was obtained from hospital discharges; annual hip fracture rates were determined and standardized using the Spanish 2002 population census. A linear regression was performed between fracture rate and use of bisphosphonates; R(2) and Pearson correlation coefficient were calculated.

From 2002 to 2008, dispensed prescriptions of bisphosphonates in Spain increased from 3.28 to 17.66 DDD/1,000 inhabitants per day. In the same period, the crude hip fracture rate increased from 2.85 to 3.02 cases per 1,000 inhabitants older than 50 years; however, when age standardized rates were estimated, the rate declined from 2.85 to 2.79. Analyzed by sex, the standardized rate for men slightly increased from 1.45 to 1.48, while for women the rate significantly dropped from 4.00 to 3.91.

A small effect of bisphosphonates on hip fracture rates can not be ruled out; however, other factors might partially explain this decline. Assuming this medication was the only cause for hip fracture rate reduction, the elevated medication cost to avoid a single hip fracture makes it necessary to explore less expensive interventions.