The cost-effectiveness of risedronate in the treatment of osteoporosis:: an international perspective

Introduction: Risedronate, a bisphosphonate for treatment and prevention of osteoporosis, has been shown in several clinical trials to reduce the risk of fractures in postmenopausal women with osteoporosis. The cost-effectiveness of risedronate treatment has previously been evaluated within different country settings using different model and analysis approaches. The objective of this study was to assess the cost-effectiveness of risedronate in postmenopausal women in four European countries-Sweden, Finland, Spain, and Belgium-by making use of the same modelling framework and analysis setup. Methods: A previously developed Markov cohort model for the evaluation of osteoporosis treatments was used to estimate the cost-effectiveness of risedronate treatment. For each country, the model was populated with local mortality, fracture incidence, and cost data. Hip fractures, clinical vertebral fractures, and wrist fractures were included in the model. Results: The incremental cost per quality-adjusted life years (QALY) gained from a 5-year intervention with risedronate compared to "no intervention" in 70-year-old women at the threshold of osteoporosis [T-score = -2.5 based on National Health and Nutrition Examination Survey (NHANES) III data] and previous vertebral fracture was estimated to be E860, E19,532, E11,782, and E32,515 in Sweden, Finland, Belgium, and Spain, respectively. Among 70-year-old women at the threshold of osteoporosis without previous fracture the estimated cost per QALY gained ranged from E21,148 (Sweden) to E80,100 (Spain). The differences in cost-effectiveness between countries are mainly explained by different costs (fracture and treatment costs), fracture risks, and discount rates. Based on cost per QALY gained threshold values found in the literature, the study results indicated risedronate to be cost effective in the treatment of elderly women with established osteoporosis in all the included countries. Conclusions: At a hypothetical threshold value of E40,000 per QALY gained, the results in this study indicate that risedronate is a cost-effective treatment in elderly women at the threshold of osteoporosis (i.e., a T-score of -2.5) with prevalent vertebral fractures in Sweden, Finland, Belgium, and Spain.