Methods: We developed a microsimulation model to compare a strategy of no screening to four other strategies: screening with dual-energy x-ray absorptiometry (DXA) testing, pre-screening with quantitative ultrasound (QUS) testing with subsequent performance of DXA if QUS positive, pre-screening with a risk assessment tool (the Simple Calculated Osteoporosis Risk Estimation (SCORE)) with subsequent performance of DXA if SCORE positive, and universal treatment with alendronate medication therapy. We used published data on osteoporosis prevalence, fracture rates, health state utility values, treatment efficacy, and screening test accuracy for model inputs, using U.S. data sources whenever possible. Our base-case population was average risk postmenopausal women 65 years of age. We used a lifetime time horizon and societal perspective, discounted costs and QALYs at a 3% annual rate, and present results in 2003 U.S. dollars.
Results: In our base-case analysis, the incremental cost-effectiveness ratios (ICERs) were similar for the pre-screening with QUS strategy and the pre-screening with SCORE strategy, approximately $39,000/QALY compared to no screening. The ICER for the DXA screening strategy was $28,000/QALY compared to pre-screening with QUS or SCORE. Both pre-screening strategies were dominated by the principal of extended dominance by a blend of DXA screening and no screening strategies. The ICER for universal treatment with alendronate was $117,000/QALY compared to the DXA screening strategy. Reduction in the cost of alendronate to 50% of its current value reduced its ICER to approximately $65,000/QALY compared to the DXA screening strategy.
Conclusions: Screening average risk 65 year old postmenopausal women for osteoporosis using DXA is highly cost-effective. Pre-screening strategies with either QUS or the SCORE risk assessment tool are cost-effective compared to no screening, but are dominated by the principal of extended dominance by a blend of DXA screening and no screening. Universal treatment of 65 year old postmenopausal women with alendronate is expensive; however, significant reduction in the cost of alendronate therapy would make universal treatment a more cost-effective option.