[Embargoed for release until 4 PM, May 27, 2003, to coincide with publication in the Journal of the American Medical Association.]
STROKE RISK INCREASES WITH USE OF COMBINED HORMONE THERAPY
COLUMBUS, Ohio – Healthy older women who take estrogen and progestin combined, the most common form of hormone replacement therapy, have a higher risk of suffering a stroke, according to new findings from the Women’s Health Initiative (WHI).
The study’s authors conclude that the risks associated with combined hormone therapy outweigh its potential benefits. Their report is published in the May 28 issue of the Journal of the American Medical Association.
The study of 16,608 postmenopausal women between the ages of 50 and 79 suggests that those taking estrogen plus progestin had an overall 31 percent higher risk of stroke than women taking a placebo. Of those studied, 151 patients taking hormones had strokes, compared with 107 in the placebo group.
Almost 80 percent of strokes were ischemic, which are characterized by blockage of a cerebral artery. The hormone therapy group had a 44 percent increased risk for ischemic stroke compared to those taking placebo. The risk for hemorrhagic stroke, characterized by bleeding in the brain, did not significantly differ among the two groups studied.
“Though the women in the trial exhibited a variety of other risk factors for stroke, which we took into account and which affected the onset of increased risk, the adverse effects of estrogen plus progestin were demonstrated across the diverse population studied,” said W. Jerry Mysiw, a physical medicine and rehabilitation specialist at The Ohio State University Medical Center and a co-author of the study.
Among the risk factors that researchers determined did not modify the effects of estrogen plus progestin on stroke risk were age, smoking, high blood pressure, diabetes, history of cardiovascular disease and lower use of vitamin C supplements.
Women in the estrogen plus progestin part of the Women’s Health Initiative stopped taking their study pills in July after research results indicated that for those on the combined therapy, the overall risks (breast cancer, heart attacks, stroke and blood clots) outweighed the benefits (fewer fractures and colorectal cancers). This report expands on those initial findings by examining subtypes of stroke and providing additional data on the effects of the combined hormone therapy in various subgroups of women.
Mysiw noted that the study does not address the issue of short-term hormone use for postmenopausal symptoms or for perimenopausal use of hormones.
“Defining exactly what could be considered safe short-term use is problematic,” Mysiw said. “What we do know is the excess risk for stroke became apparent by the second year of combined hormone use.”
The women in the study were followed for an average of 5.6 years at the WHI’s 40 clinical centers in the United States, including OSU Medical Center, where Mysiw is part of the team of Women’s Health Initiative investigators.
The study drug and placebo were supplied by Wyeth-Ayerst Research Laboratories, manufacturer of Prempro, the brand name of the combined estrogen and progestin therapy. The study was funded by the National Heart, Lung, and Blood Institute.
Contact: Emily Caldwell, Medical Center Communications, 614-293-3737 or firstname.lastname@example.org