Stroke risk declines after cessation of HRT
MedWire News: The increased risk for stroke among women taking hormone replacement therapy (HRT) dissipates soon after stopping treatment, shows follow-up of the Women's Health Initiative (WHI).
The WHI Estrogen-Alone Trial randomly assigned 10,739 postmenopausal women with prior hysterectomy to receive conjugated equine estrogens (CEE) or placebo. The trial was halted a year early, after an average of 7.1 years, because of a significantly increased risk for stroke and deep vein thrombosis (DVT) among estrogen users.
The present study, which appears in JAMA, followed-up the women for an average of 10.7 years after treatment initiation (about 4 years after HRT cessation).
During this period, the annual risk for stroke was 0.36% among women who were formerly taking HRT, compared with 0.41% in the placebo group, which was not a significant difference. The corresponding risks for DVT were 0.17% and 0.27%, which significantly favored HRT.
The annual risk for breast cancer during the postintervention period was somewhat lower in the HRT group compared with the placebo group, at 0.26% versus 0.34%. Over the entire trial period, including intervention, breast cancer risk was significantly lower among HRT users, at 0.27% versus 0.35% in the placebo group.
"A postmenopausal woman who has had a hysterectomy and is considering initiation of CEE should be counseled about the increased risks of venous thromboembolism and stroke during treatment, which diminish with treatment cessation," say Andrea LaCroix (Fred Hutchinson Cancer Research Center, Seattle, Washington, USA) and colleagues.
Over the entire follow-up period, taking HRT was associated with a reduced risk for coronary heart disease and myocardial infarction in women aged 50-59 years, but an increased risk for colorectal cancer in those aged 70-79 years.
"Our results emphasize the need to counsel women about hormone therapy differently depending on their age and hysterectomy status," the team concludes.
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By Eleanor McDermid