Changes in the Use of Postmenopausal Hormone Replacement Therapy after the Publication of Study Results

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The summary below is from the full report titled "Changes in the Use of Postmenopausal Hormone Therapy after the Publication of Clinical Trial Results." It is in the 3 February 2004 issue of Annals of Internal Medicine (volume 140, pages 184–188). The authors are J.S. Haas, C.P. Kaplan, E.P. Gerstenberger, and K. Kerlikowske.

What is the problem and what is known about it so far?

Menopause is the time when a woman's ovaries permanently decrease production of the hormones estrogen and progesterone. This reduction in hormone levels leads to the end of menstruation. In the years around menopause, the changes in hormone levels result in symptoms, including hot flashes, night sweats, mood swings, and vaginal dryness. The lower hormone levels also put women at risk for osteoporosis and heart disease. Postmenopausal hormone replacement therapy (HRT) refers to regimens of the female hormone estrogen with or without progesterone. Hormone replacement therapy reduces the uncomfortable symptoms of menopause. It also influences the development (favorably and unfavorably) of conditions including osteoporosis (thinning of the bones that can lead to fractures), heart disease, stroke, blood clots, dementia, and cancer (colon, breast, and uterine). Before the publication of the results of 2 large studies, the Heart and Estrogen/progestin Study (HERS) in 1998 and the Women's Health Initiative (WHI) in 2002, research suggested that the benefits of HRT outweighed the risks. However, HERS and the WHI, which were of higher quality than previous studies, showed that women taking HRT actually had a higher risk for heart disease and stroke than women not taking HRT. The results of the WHI received substantial media attention.

Why did the researchers do this particular study?

To describe changes in HRT use after publication of the 2 largest and best-quality studies on HRT.

Who was studied?

Postmenopausal women who underwent mammography in San Francisco, California, between January 1997 and 19 May 2003.

How was the study done?

At the time of each mammogram, women answered questions about their health and HRT use. The researchers looked at the proportion of women who were taking HRT each quarter year over the study period. They were most interested in patterns of use after publication of HERS in August 1998 and the WHI in July 2002.

What did the researchers find?

The proportion of women who were taking HRT was increasing slowly in the period before HERS publication but decreased slightly after HERS publication in 1998 and decreased dramatically after WHI publication in 2002. The decreases in use were not associated with age, hysterectomy status, or ethnic background.

What were the limitations of the study?

The results might not apply to women in other geographic areas or women who do not undergo mammography. In addition, the study ended too soon to show whether the decreases in HRT use after WHI publication continued, stabilized, or started to rise.

What are the implications of the study?

The changes in HRT use following WHI publication are more dramatic than those usually seen with the publication of new studies. The large amount of media attention and the fact that the WHI was the second large study to show that the risks of HRT may outweigh the benefits may have contributed to the changes.