Incidence, risk and evolution of ostheoporotic hip fractures in Spanish women using a Markov type model

To estimate osteoporotic hip fracture incidence rates, by age and gender, and lifetime fracture risk of women of different age groups over 45 in Spain, and to determine the expected number of fractures and fracture-related person-years of functional impairment, as a basis for estimating the social costs of osteoporosis in Spain and the avoided costs of fractures in future cost-effectiveness analyses.

The natural history of disease, recognized from fractures, is described using a Markov model and MonteCarlo simulations. Four cohorts of 10,000 women, each of a different age group, were simulated. Data were obtained from six hospitals of different size and geographical setting, to allow for differences in hospital service structure. Patients included were all new cases of hip fracture who were attended in those hospitals in 1995. Results are extrapolated to the Spanish population based on 1991 census.

We can predict in the group of women aged 50 an over in Spain 968,000 osteoporotic hip fractures during their remaining lifetime, with a total amount of 1,013,000 fractures. Some 135,000 will become functionally impaired due to the fractures, accounting for 1,177,000 person-years of functional impairment.

The study provides a prototype for estimating avoided costs of fractures in future cost-effectiveness analyses.