HRT Unlikely to Have Cardioprotective Effects

Hormone replacement therapy (HRT) may increase a woman’s risk of stroke and should not be considered as a way to protect against cardiovascular disease, a recent meta-analysis concluded.

Key Points:

- HRT may increase a woman’s risk of stroke and should not be considered a therapy that is cardioprotective.

- Women younger than 60 who use HRT were less likely to have heart disease or die from a cardiac event. However, their risk of blood clots was increased.

- Clinicians must continue to carefully weigh the benefits of HRT with the possible harms, including increased risk of breast cancer, ovarian cancer, and thromboembolism.

Evidence from 19 randomized controlled trials involving more than 40,000 women suggests that the once-held belief that HRT during menopause could ward off cardiovascular disease is wrong. The analysis was conducted as an update to the 2013 review by the Cochrane Heart Group and included 6 new studies.

Overall, the combined study results showed no evidence that HRT provides a protective effect against death from any cause. Specifically, the authors reported that the absolute risk increase for stroke was 6 per 1000 women (number needed to treat for an additional harmful outcome (NNTH) = 165; mean length of follow-up: 4.21 years (range: 2.0 to 7.1)); for venous thromboembolism, 8 per 1000 women (NNTH = 118; mean length of follow-up: 5.95 years (range: 1.0 to 7.1)); and for pulmonary embolism, 4 per 1000 (NNTH = 242; mean length of follow-up: 3.13 years (range: 1.0 to 7.1)).

Still, the authors do not go as far as to discount entirely the clinical use of HRT. Instead, they say a woman’s age, her symptoms and medical history should be accounted for when discussing the possibility of treatment.

In addition, the editors did find one subgroup of women who could see a potential benefit to taking hormones during menopause. Women younger than 60 years old who started HRT were found to have a reduced likelihood of heart disease as well as fewer deaths. Still, while they had 8 fewer cases of heart disease, they also experienced 5 extra blood clots over about 7 years, compared with a group of similar women who did not start HRT.

“This review adds a few more pieces to a complicated jigsaw of evidence relating to the use of HRT to treat symptoms of menopause,” said David Tovey, MD, Editor in Chief of the Cochrane Library, in a news release. “The main analysis that the authors did found no benefit, and so we need to apply caution to the results from the subgroup analysis. However, if true, this apparent benefit in preventing heart disease in younger women should be considered alongside other possible benefits and emerging evidence of harms, including the risk of breast cancer, ovarian cancer, and DVT [deep vein thrombosis].”