Hormone replacement therapy (HRT) skin patches containing low doses of estrogen carry less risk of stroke than oral therapy and may represent a safer alternative to tablets, suggests a study conducted by researchers at the Lady Davis Research Institute of the Jewish General Hospital. Their study was published June 4 in the British Medical Journal (BMJ).
The study was led by Dr. Samy Suissa, head of the Centre for Clinical Epidemiology at the Lady Davis Institute, with colleagues from the Centre and Germany. Suissa and his team found that low-dose patches have 26 percent less risk than oral forms of HRT, they said, though the risk with patches is elevated with higher doses.
HRT is regularly prescribed to women suffering from the effects of menopause. Recent studies have shown an increased risk of stroke associated with taking HRT in oral forms. However, no studies had examined this risk with different doses or routes of administering HRT.
“Oral forms of the estrogen pass through the liver, where they can induce inflammation or clotting effects that can be associated with cardiovascular events,” said Dr. Suissa, also a professor of epidemiology and biostatistics at McGill University. “With the patch, you’re bypassing the liver.”
Dr. Suissa and his colleagues assessed the risk of stroke associated with oral and transdermal (through the skin) HRT in post-menopausal women in the UK. Their findings are based on data from the General Practice Research Database (GPRD), which holds the anonymized medical records of millions of patients registered with family doctors across the UK.
From a population of over 870,000 women aged 50-79 between January 1987 and October 2006, they identified 15,710 cases with a first recorded diagnosis of stroke occurring in the study period. Each case was matched to 59,958 controls.
The risk of stroke was not increased with use of low estrogen dose patches compared with no use, whereas the risk was increased with high-dose patches.
Use of oral HRT increased the rate of stroke by around 25 to 30 percent compared with no use, regardless of the estrogen dose or when combined with progestogen, confirming previous studies.
Suissa urges clinicians to seriously consider these results when deciding which formulation to prescribe for their patients.
“These data are compelling, particularly in regard to the dosing,” he said. “Clinicians should consider this safer alternative, particularly for patients at higher risk of stroke.”
About the Lady Davis Institute for Medical Research at the Jewish General Hospital
The Lady Davis Institute for Medical Research (LDI), located in Montreal, Quebec, is the research arm at the Jewish General Hospital, and has strong academic ties to McGill University. With over 150 affiliated researchers, the LDI is one of the largest and most important biomedical research institutes in Quebec and all of Canada. Major breakthroughs have been made by LDI researchers in the areas of HIV/ AIDS, aging, cancer, vascular disease, epidemiology and psychosocial science, and have thereby contributed to the health and well-being of millions of patients in Montreal, across Quebec and around the world.
About the Jewish General Hospital
Now in its landmark 75th year of providing Care for All, the Jewish General Hospital has been a mainstay of superior medical care for generations of patients of all backgrounds. One of Quebec’s largest and busiest acute-care hospitals, the JGH is committed to improving the quality of healthcare for all Quebecers in partnership with the provincial healthcare network. In this anniversary year, the Jewish General Hospital has redoubled its commitment providing patients the best possible care in a clean, safe and human-centered environment. The JGH is able to deliver these pioneering, innovative medical services by strengthening its role as a McGill University teaching hospital, by expanding and upgrading its facilities, and by pursuing cutting-edge research at the Lady Davis Institute for Medical Research. Website: jgh.ca