For many women, stopping hormone replacement therapy (HRT) may involve significant medical risk, recent research has found.
HRT can relieve menopause symptoms such as vaginal dryness, hot flashes and difficulty sleeping. However, many women stop treatment to avoid increasing their risk of conditions including uterine cancer, breast cancer and deep vein thrombosis.
That decision may involve dangers of its own. A recent Finnish study observed more than 332,000 women age 40 and older who had discontinued HRT between 1994 and 2009. It found significantly higher risk for cardiovascular death within the first year following HRT cessation, as well as increased likelihood of death due to stroke in the first year post-treatment. Both cardiovascular and stroke death risk decreased after one year. Women who discontinued HRT before age 60 were at even higher risk for cardiac mortality.
“We hope the main reason for women to discontinue [hormone replacement therapy] is that they don’t need it anymore. However, due to the fear of using HRT, many women ... annually or biannually try to manage without HRT.” Tomi Mikkola, MD, Associate Professor of Obstetrics and Gynecology at Helsinki University Hospital
The observational study cannot demonstrate clear cause and effect, says Tomi Mikkola, MD, Associate Professor of Obstetrics and Gynecology at Helsinki University Hospital and lead author of the study, published in The Journal of Clinical Endocrinology & Metabolism. There are several possibilities, however.
“Estrogen has rapid vasodilatory effects in the coronary and carotid arteries mediated by vasodilatory agents, such as nitric oxide and prostacyclin,” Dr. Mikkola says. “Estrogen also inhibits the release of endothelin-1, the most potent vasoconstrictor. Therefore, estrogen withdrawal, as in discontinuation of HRT, may result in arterial constriction. This could endanger adequate coronary circulation, for example in women with unstable angina. These changes may result in potentially fatal myocardial infarction. Furthermore, women with vasomotor hot flashes also frequently report palpitations or arrhythmias. Since HRT prevents vasomotor hot flashes and palpitations, HRT withdrawal could predispose some women to fatal arrhythmias.”
Rethinking the Approach
According to Dr. Mikkola, the research has additional implications for women who cease HRT, restart treatment because of recurring menopause symptoms, then stop it again due to fear of side effects. A broad spectrum of research supports careful use of HRT, he adds.
“Several observational studies, randomized controlled trials and meta-analyses indicate that when initiated close to menopause, HRT reduces mortality,” he says.
Howard N. Hodis, MD, Harry J. Bauer and Dorothy Bauer Rawlins Professor of Cardiology, Professor of Medicine and Preventive Medicine, Molecular Pharmacology and Toxicology, and Director of the Atherosclerosis Research Unit at the Keck School of Medicine at the University of Southern California, is troubled by what he sees as irrational fear of HRT.
“The pain and suffering many women endure because they are scared or their doctor is scared need to stop ...,” Dr. Hodis says. “These drugs are safe. The risks are no greater than any other drugs we use.”