Effect of the Women's Health Initiative on osteoporosis therapy and expenditure in Medicaid

Abstract

Decreasing HRT use among postmenopausal women may have a reciprocal impact on other osteoporosis therapy. Time series analysis of prescribing trends for millions of Medicaid beneficiaries revealed a 57% decline in HRT without augmenting the pace of bisphosphonate use. Prescribing changes dramatically increased Medicaid spending on osteoporosis therapy over the last decade and requires further evaluation of cost effectiveness.

Introduction: Hormone replacement therapy (HRT) has been commonly prescribed to postmenopausal women, but its use is decreasing because adverse cardiac outcomes were reported by the Women's Health Initiative (WHI) in July 2002. The reciprocal impact of the WHI on other osteoporosis medications use and expenditure is unknown.

Materials and methods: We conducted a time series analysis on prescription data from 50 state Medicaid programs between 1995 and 2004. Five medication categories were used: HRT, bisphosphonates, calcium, calcitonin, and raloxifene.

Results: HRT was increasing before publication of the WHI, reaching 5 million prescriptions per year by mid-2002 (136 prescriptions per 1000 beneficiaries). Bisphosphonate prescribing rose in parallel until mid-2002. WHI publication was associated with a rapid reduction in HRT use, declining 57% by mid-2004 to an average of 59 prescriptions per 1000 beneficiaries (p = 0.01). WHI publication did not augment bisphosphonates' nearly linear rate of rise (p = 0.43) as their prescribing pace continued, whereas HRT declined. Medicaid spending on osteoporosis therapy also changed dramatically during the last decade, as yearly expenditure increased 664% from 1465 US dollars to 9742 US dollars per 1000 beneficiaries. Over this period, a significant shift from daily to weekly bisphosphonates also occurred.

Conclusions: A dramatic decline in HRT and continued rise in bisphosphonate prescribing has occurred since the publication of the WHI. During this time, there have also been substantial increases in osteoporosis medication spending within Medicaid. Determining whether these trends are clinically appropriate and cost effective for osteoporosis therapy will have important implications for the development of future drug reimbursement programs, especially for elderly patients.