Cost effectiveness of alendronate (Fosamax®) for the treatment of osteoporosis and prevention of fractures

Background: The Fracture Intervention Trial (FIT) demonstrated that the bisphosphonate alendronate reduces the risk of hip, spine and wrist fracture in osteoporotic women by approximately one half. Objective: To use data from FIT to conduct a cost-effectiveness analysis of alendronate. Design: A Markov model was developed for a cohort of Swedish women, comparable in relative fracture risk to the women enrolled in the FIT vertebral fracture arm (i.e. age 71 years with low bone mass plus at least one prior spine fracture). The women in the model (with low bone mass and a previous spine fracture) were exposed to alendronate therapy and transitioned over time from a `well' health state to health states of `hip fracture', `spine fracture', `wrist fracture' or `death'. All costs were calculated in 2000 Swedish kronors (SEK). Time horizon: In the Markov model our base-case treatment duration was 5 years followed by a 5-year period where the benefit, declined linearly to 0. Results: We found that treating 71-year-old osteoporotic women with a prior spine fracture with alendronate resulted in a cost per quality-adjusted life-year (QALY) gained of SEK76 000, which is well below the threshold for cost effectiveness of SEK300 000. For women aged 65 years, the cost-effectiveness ratio increased to SEK173 000 and for women aged 77 years, the cost-effectiveness ratio decreased to SEK52 000. Conclusions: Treating older osteoporotic women with alendronate was more cost effective than treating younger women with osteoporosis, and treating osteoporotic women with prior spine fracture was more cost effective than treating osteoporotic women without prior spine fracture. However, the costs per QALY gained for all populations studied were below generally accepted thresholds for cost effectiveness.