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Danish hormone replacement therapy study challenges HRT risks

by Jennifer-Leigh Oprihory
Oct 10, 2012


Increased risk of mortality and heart ailments previously linked to hormone-replacement therapy may have been a result of delayed treatment times rather than of the treatment itself, according to a Denmark-based study published Tuesday by the British Medical Journal.

However, the pool of study participants - fit, white females who tended to smoke - may impede the applicability of study findings to other patient communities, notes an expert here.

The study, involving more than 1,000 women, demonstrated a decreased risk of death and heart ailments in women who underwent a 10-year hormone-replacement therapy regimen that started immediately after the onset of menopause. The study showed no increased risk of cancer, deep-vein thrombosis (a type of blood clot) or stroke associated with HRT. 

The study was conducted in response to questions as to whether treatment timing—the amount of time after menopause before hormone replacement therapy began— was linked to past heart and health-related outcomes in patients. Early treatment maximizes the potential health benefits of HRT, according to the study. 

The study funders included the University of Aarhus, the Karen Elise Jensen's Foundation and also pharmaceutical companies. "None of the funders had any influence on the study design, interpretation of data or the decision to publish the results," according to study authors.

According to a BMJ press release published today, the study followed a total of 1,006 women (504 of whom were treated with hormone-replacement therapy for 10 years as early as possible after  menopause and 502 who were not treated with it at all) during the treatment period. The women's health remained under observation for six years after treatment concluded in 2002.

"After 10 years of treatment the hormone-replacement therapy women had a 50 percent reduced risk of a cardiovascular event or death,” wrote Dr. Louise Lind Schierbeck in an email. She is an investigator for the study and did the research at Hvidovre Hospital near Copenhagen. She is now a physician with Bispebjerg Hospital in Denmark.“This persisted after the intervention stopped, thus 6 years later the risk was still reduced with 40 percent in the women who had received hormone-replacement therapy.”

The article states that group receiving hormone-replacement therapy experienced close to 50 percent fewer documented deaths (15) than did the untreated group (26). The same trend followed for the number of women experiencing what the paper calls a “primary composite endpoint,” or a hospital admission for heart failure, an occurrence of myocardial infarction or death after the beginning of the study, in a ratio of 16:33.

“I think that they confirm what a lot of us have felt already," said Dr. Suzanne Kavic, Division Director for Reproductive Endocrinology at Loyola University Medical Center. "If you give hormone replacement in women who are close to their menopause, which is when we always intended to give it, that can be beneficial.”

“Some of the earlier studies—WHI [The Women’s Health Initiative] in particular—really did look at an older population of women, and, as you might expect, they would have more complications because they’re older and they have more preexisting disease,” Kavic said.

The WHI study was discontinued on May 31, 2002  in response to an advisory board’s recommendation to discontinue it in response to an overabundance of serious side effects including coronary heart disease, breast cancer and stroke.

The WHI study includes documentation of participants’ histories of heart problems, stroke, blood clots and cancer in its baseline characteristics data.

Notably, the lower age limit for the WHI study was set at 50 (five years older than the minimum age for the Danish study). The Danish study also differs in its methodical approach, including only healthy women and excluding women with histories of  “bone disease, uncontrolled chronic disease, previous or current cancer or thromboembolic disease,  current or past treatment with glucocorticoids for more than six months, current or previous use of hormone replacement therapy within the past three months, and alcohol or drug dependency,” according to the BMJ study article.

While Kavic praised the Scandinavian patient tracking model in enabling long-term studies like this one, she expressed concerns over the lack of diversity in the study population. 

“They have a phenomenal registry. So, because of their healthcare system, they’re able to follow patients long term. They lose very few patients to follow-up because they have great tracking systems, so they really get some wonderful data. But a limitation of that is the patients are very homogenous,” she said. The study population consisted of white, fit women who, in many cases, smoked.

In contrast, the Women’s Health Initiative study included more than 16,000 women and included whites, blacks, Hispanics and Asian/Pacific Islanders.

 

“The study was conducted in Denmark, thus Danish women were recruited (at the time the study was initiated the percentage of other ethnicities in the postmenopausal age was very small),” Schierbeck wrote in the same email. “The women were generally healthy and recently postmenopausal (max. two years post-menopause).”

“Can you extrapolate this to all of the patient populations?” asked Kavic. “That’s a very good question.”

“I think more studies like this, with maybe a more diverse population, would maybe be very helpful,” Kavic said.

For more information:

BMJ Official Press Release:http://www.bmj.com/press-releases/2012/10/10/hrt-taken-10-years-significantly-reduces-risk-heart-failure-and-heart-atta
BMJ Article: http://www.bmj.com/cgi/doi/10.1136/bmj.e6409
Women's Health Initiative - 2002 Article on the JAMA Website: http://jama.jamanetwork.com/article.aspx?articleid=187879