The long-term effectiveness of preventive strategies for osteoporosis in postmenopausal women: A modeling approach

Based on data from the literature, we have developed a computer-based simul ation model to compare the long-term effectiveness of different preventive strategies of osteoporotic fractures. The Markov model comprises 25 states, including states which describe women distributed according to three level s of fracture risk, fractures states, post-fracture states and a death stat e. We chose eight standard preventive strategies, which we compare with the 'No Treatment' reference strategy. The first two strategies consist in tre ating all 50-year-old women for 5 or 10 years with hormone replacement ther apy (HRT). Strategies 3 and 4 aim at assessing a 5-year course of treatment with bisphosphonates in osteopenic and osteoporotic 65- or 75-year-old wom en. Strategies 5 and 6 combine 5 years of HRT in all 50-year-old women with 5 years of bisphosphonates in osteopenic and osteoporotic women at 65 or 7 5 years. The last two strategies simulate 10 years of HRT in all 50-year-ol d women, followed by strategy 3 or strategy 4. Simulated life expectancy an d mean ages of fracture occurrence fit well with the observed data. All the preventive strategies tested reduced the number of fractures. Early 10-yea r HRT in all women, plus 5 years of bisphosphonates in women at risk Of fra ctures at 65 or 75 years, are the most effective strategies, with an 18.4-1 9.0% reduction in all fractures, and a 25.6-26.1% reduction in the number o f hip fractures. Strategy 2 has a similar outcome, thus demonstrating the v alue of treatment started early and sustained over a long period. The strat egies implemented later, S3 and S4, only concern women at risk (i.e., osteo penic or osteoporotic), and are less effective, with a 1.5-2.1% decrease in all fractures. The combined strategies, S5 and S6, produce intermediate re sults: a 12.9-13.5% reduction in the number of all fractures and a 17.5-17. 9% reduction in hip fractures.