A cost-effectiveness model of tibolone as treatment for the prevention of osteoporotic fractures in postmenopausal women in Sweden

Background: Osteoporosis is a major cause of morbidity and mortality in the elderly and, in particular, among postmenopausal women. Hormone replacemen t therapy (HRT) has been shown to protect against fractures, as well as to alleviate climacteric symptoms related to menopause. Unfortunately, HRT has a number of adverse effects and many patients are noncompliant. Tibolone, a synthetic steroid with tissue-specific estrogenic, progestogenic and andr ogenic effects, has been shown to prevent the loss of bone mass as well as to relieve climacteric symptoms in postmenopausal women, with fewer accompa nying adverse effects. Objective: To estimate the economic impact in Sweden of administering tibol one 2.5 mg/day to postmenopausal women at risk for osteoporosis-related bon e fractures relative to a policy of no intervention. Design and Setting: Modelling study performed from the national health syst em perspective in Sweden. Methodology: Disease modelling was used to simulate the risks of osteoporos is-related hip, vertebral and forearm fractures over time in hypothetical c ohorts of postmenopausal women. The occurrence of fractures was predicted u sing risk functions estimated with data from actual cohorts of women in Swe den as well as the USA. Sweden-specific cost data were then used to estimat e the economic impact with cost-effectiveness tools. Results: The model predicts that 22% of hip fractures and 13% of combined h ip, vertebral and forearm fractures can be avoided over a 25-year time-peri od by administering tibolone to osteoporotic women. Depending on the severi ty of loss in bone mass and the values assumed for key parameters, estimate s of the cost effectiveness of treatment range from cost saving to incremen tal costs per quality-adjusted life-year (QALY) gained of around SEK200 000 . Delaying treatment to late menopause tends to decrease cost effectiveness . Conclusion: Our findings suggest that, relative to no treatment, tibolone i s a cost-effective treatment in Sweden for the prevention of fractures in w omen with low bone mass,especially when treatment is initiated around the o nset of menopause and is administered for 5 years.