The impact of the Women's Health Initiative on hormone replacement therapy in a Medicaid program.

BACKGROUND: Observational studies suggest that hormone replacement therapy (HRT) reduces women's risk of cardiovascular disease (CVD). However the Women's Health Initiative (WHI) HRT arm was stopped early because of increased risk of CVD, stroke, pulmonary embolism, and breast cancer. Evaluating HRT-prescribing patterns in relation to the release of the WHI will help determine if these study results have influenced the use of HRT.

METHODS: This is a descriptive time series analysis to primarily evaluate utilization trends of HRT in women > or =50 years enrolled in the Pennsylvania Medicaid Program. HRT was categorized as follows: conjugated equine estrogen (CEE) plus medroxyprogesterone acetate (MPA), CEE only, and other estrogens/progesterone combinations.

RESULTS: The overall prevalence of HRT decreased significantly post-WHI study release for all age and racial groups. The prevalence of CEE plus MPA decreased throughout the study; however, the prevalence of HRT declined at a faster rate after the WHI study release among women in their 50s and 60s compared with women in their 70s and 80s. There was a statistically significant reduction in all types of HRT use.

CONCLUSIONS: The WHI influenced all types of HRT use among postmenopausal women in a Medicaid program. Administrative claims data can be a useful tool for monitoring an immediate impact of national guidelines or a national level outcomes trial.