Hormone Replacement Therapy: An Analysis Focusing On Drug Claims By Female Seniors, 2000 To 2007

Main Category: Women's Health / Gynecology
Also Included In: Endocrinology
Article Date: 20 Jun 2008 - 3:00 PDT

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The use of hormone replacement therapy (HRT) by senior Canadian women in five provinces has dropped from 14% to 5% since the publication of the 2002 Women's Health Initiative (WHI) study, which found the health risks of using HRT outweighed the benefits. A new analysis of public drug claims from the Canadian Institute for Health Information (CIHI) shows that the use of HRT among female seniors (aged 65 and older) in five provinces declined each year between 2001-2002 and 2006-2007, with the highest average annual rate of decline (30%) occurring in the two-year period following the publication of the WHI study. The five provinces included in the CIHI analysis were Alberta, Saskatchewan, Manitoba, New Brunswick and Nova Scotia.

"Up until the late-1990s, many women were prescribed hormone replacement therapy because of its success in relieving the symptoms of menopause and its reported protective benefits in coronary heart disease and osteoporosis," says Dr. Jennifer Blake, obstetrician and gynecologist in chief at Sunnybrook Health Sciences Centre in Toronto. "New evidence highlighting the potential risks of HRT, as well as its lack of benefit in preventing heart disease, has forced caregivers and patients to re-examine its use, particularly in elderly patients. CIHI's study highlights a great example of how new information can be used to immediately improve practices and advance patient safety."

Declines reported in both estrogen-only and combination HRT

The first reports of possible side effects associated with estrogen-only hormone replacement treatment, namely an increased risk of endometrial cancer, began to emerge in the 1970s, leading to the development of what is now known as combination (progestin and estrogen) therapy. Later studies, such as the 2002 WHI study, identified important additional risks with the combination therapy, such as an increased risk of coronary heart disease and stroke.

While the use of both types of HRT decreased over the six years of the study, the decline in the use of combination HRT among female seniors was more pronounced than the decrease in the use of estrogen-only HRT. The vast majority of female seniors still using HRT in 2006-2007 were on estrogen-only regimens (84%), but rates of use varied between the five provinces included in CIHI's study.

In 2006-2007, after adjustment was made for age, the rate of estrogen-only HRT use varied across the provinces from 3.1% to 5.4%, while combination HRT use ranged from 0.5% to 1.1%.

Women still using HRT, but at lower doses

The CIHI analysis also looked at the dosage of estrogen being used by female seniors. About 75% of female seniors using HRT were on oral conjugated estrogens in doses of either 0.3 mg or 0.625 mg in 2006-2007. Of those using the higher (0.625 mg) dose in 2000-2001 and still using HRT in 2006-2007, 37% had switched to the lower (0.3 mg) dose.

"Current Canadian menopause guidelines recommend that both estrogen-only and combination HRT be taken at the lowest effective dose," says Blake. "For some women, when taken properly and monitored closely, HRT can be helpful in alleviating the symptoms of menopause and in guarding against osteoporosis."

About CIHI

The Canadian Institute for Health Information (CIHI) collects and analyzes information on health and health care in Canada and makes it publicly available. Canada's federal, provincial and territorial governments created CIHI as a not-for-profit, independent organization dedicated to forging a common approach to Canadian health information. CIHI's goal: to provide timely, accurate and comparable information. CIHI's data and reports inform health policies, support the effective delivery of health services and raise awareness among Canadians of the factors that contribute to good health.

http://www.cihi.ca