Modeling the annual costs of postmenopausal prevention therapy: raloxifene, alendronate, or estrogen-progestin therapy

To estimate the annual cost and outcome impacts attributable to raloxifene, alendronate, and estrogen-progestin therapy as prevention therapies among postmenopausal women over the first 7 years of hormone replacement therapy (HRT).

A budget-impact model was devised to compare the costs, benefits, and costs per event avoided for various postmenopausal therapies (raloxifene, alendronate, or estrogen-progestin combination therapy), compared to no intervention, taking into account the persistency rates. Net costs are direct medical costs attributable to treatments relative to no intervention. Net benefits are defined as the number of events avoided as a result of therapy. The main outcome measures are annual total net costs, net benefits, and costs per event avoided compared to no intervention among postmenopausal white women with intact uteri and normal baseline risks for osteoporotic hip or vertebral fractures, fatal or nonfatal myocardial infarction, and breast cancer. Data and model assumptions are based on clinical trial data and published retrospective studies.

The average annual net cost of therapy declines after the first year of therapy for all interventions, primarily due to discontinuation, and continues to decline over time due to savings in medical costs for events avoided. Net events avoided are greater for raloxifene than alendronate, but HRT use results in net harm. The cost per event avoided is lower for raloxifene than alendronate. Improved persistence improves the cost-effectiveness for both interventions. Sensitivity analyses indicate the model results are most sensitive to the assumed impact of raloxifene on coronary heart disease and breast cancer risk. Alendronate as a prevention intervention is dominated by raloxifene under almost all model scenarios.

The annual cost of long-term postmenopausal prevention therapy is highest during the first few years of therapy. Long-term prevention does not provide a return on investment in fewer than 3 years, but savings in medical costs partially offset intervention costs after 2 years. For postmenopausal women, pharmacologic interventions with multiple prevention benefits tend to be more cost effective than interventions with a single source of health benefit.