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

Abstract

Based on data from the literature, we have developed a computer-based simulation 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 levels of fracture risk, fractures states, post-fracture states and a death state. We chose eight standard preventive strategies, which we compare with the 'No Treatment' reference strategy. The first two strategies consist in treating all 50-year-old women for 5 or 10 years with hormone replacement therapy (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 women. 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 75 years. The last two strategies simulate 10 years of HRT in all 50-year-old women, followed by strategy 3 or strategy 4. Simulated life expectancy and mean ages of fracture occurrence fit well with the observed data. All the preventive strategies tested reduced the number of fractures. Early 10-year HRT in all women, plus 5 years of bisphosphonates in women at risk of fractures at 65 or 75 years, are the most effective strategies, with an 18.4-19.0% reduction in all fractures, and a 25.6-26.1% reduction in the number of hip fractures. Strategy 2 has a similar outcome, thus demonstrating the value of treatment started early and sustained over a long period. The strategies implemented later, S3 and S4, only concern women at risk (i.e., osteopenic or osteoporotic), and are less effective, with a 1.5-2.1% decrease in all fractures. The combined strategies, S5 and S6, produce intermediate results: a 12.9-13.5% reduction in the number of all fractures and a 17.5-17.9% reduction in hip fractures.