Termination of the estrogen plus progestin (EPT) arm of the long-term Women's Health Initiative (WHI) study was announced on July 9, 2002, due to findings that EPT use was associated with increased risk of breast cancer, coronary heart disease (CHD), stroke, venous thromboembolism, and pulmonary embolism. Following the announcement, use of EPT as well as estrogen only therapy (ET) declined. According to a study supported in part by the Agency for Healthcare Research and Quality's Centers for Education and Research on Therapeutics (CERTs) program (HS11843), this decline in hormone use was similar among women of all races, education level, and income level. Widespread media attention to the WHI EPT trial results may have resulted in comparable dissemination of this information across diverse socioeconomic groups, explain the study authors.
Researchers tracked EPT and ET continued use and initiation of use from September 1, 1999 to June 31, 2002 (baseline) and in December 31, 2002 (followup) among 221,378 women aged 40-80 years enrolled in 5 health maintenance organizations (HMOs). They categorized women by their census block, race, education, and household income. They found that the changes in prevalence, initiation, and discontinuation of both EPT and ET after release of the WHI results were similar regardless of race, education level, or household income.
In addition to the widespread media coverage of WHI trial results, the prescribing practices of HMO clinicians treating the women may also have played a role in the similar responses of different groups. In April 2004, release of the results from the WHI ET trial indicated no significant effect of ET on risks for coronary heart disease, breast cancer, colorectal cancer, pulmonary embolism, or total mortality; however, the trial indicated a 39 percent decrease in hip fracture risk and a 40 percent increase in stroke risk. How these findings may affect subsequent rates of EPT and ET use remains to be determined.
See "Changes in women's use of hormones after the Women's Health Initiative estrogen and progestin trial by race, education, and income," by Feifei Wei, Ph.D., Diana L. Miglioretti, Ph.D., Maureen T. Connelly, M.D., M.P.H., and others, in the Journal of the National Cancer Institute Monographs 35, pp. 106-112, 2005.