MEDICATIONS: TIMING OF START OF HORMONE THERAPY MAY HAVE EFFECT ON RISK OF CORONARY HEART DISEASE

April 13, 2007 — Women who initiate hormone therapy closer to menopause tend to have a reduced risk of coronary heart disease compared to women who begin treatment further from menopause, but researchers did not find this reduced risk was statistically significant, according to a study in the April 4 issue of the Journal of the American Medical Association.

Studies examining the effects of the use of postmenopausal hormone therapy on coronary heart disease (CHD) have yielded mixed results, depending on the type of study conducted. There may be a number of reasons for the differences, including the timing of initiation of hormone therapy, according to background information in the article. Jacques E. Rossouw, M.D., of the National Heart, Lung, and Blood Institute in Bethesda, Md., and colleagues conducted a secondary analysis of data from the Women's Health Initiative (WHI) trial to determine whether the effects of hormone therapy on risk of cardiovascular disease varied by age or years since menopause began. The WHI trial included 10,739 postmenopausal women who had undergone a hysterectomy who were randomized to conjugated equine estrogens (CEE) or placebo and 16,608 postmenopausal women who had not had a hysterectomy who were randomized to CEE plus medroxyprogesterone acetate (CEE + MPA) or placebo. Women ages 50 to 79 years were recruited to the study from 40 U.S. clinical centers between September 1993 and October 1998.

"Although not statistically significant, these secondary analyses suggest that the effect of hormones on CHD may be modified by years since menopause and by the presence of vasomotor symptoms [such as hot flashes or night sweats], with higher risks in women who were 20 or more years since menopause (or aged 70 years or greater). Coronary heart disease tended to be nonsignificantly reduced by hormone therapy in younger women or women with less than 10 years since menopause, and the risk of total mortality was reduced in women aged 50 to 59 years," the authors write.

"We did not have adequate statistical power to assess outcomes in the women aged 50 to 54 years or less than five years since menopause. As previously reported, CEE appeared to be associated with lower risk of CHD than CEE + MPA. Importantly, the risk of stroke was not influenced by years since menopause, the presence of vasomotor symptoms, or drug regimen, although there was no increased risk of stroke in women aged 50 to 59 years."

"The absence of excess absolute risk of CHD and the suggestion of reduced total mortality in younger women offers some reassurance that hormones remain a reasonable option for the short-term treatment of menopausal symptoms, but does not necessarily imply an absence of harm over prolonged periods of hormone use. In contrast, risk of stroke did not depend on years since menopause or the presence of vasomotor symptoms. The findings are consistent with current recommendations that hormone therapy be used in the short-term for relief of moderate or severe vasomotor symptoms, but not in the longer term for prevention of cardiovascular disease," the authors conclude.