Hormone therapy for menopausal symptoms does not increase mortality risk, according to a long-term study

By Sally Robertson, B.Sc.Sep 13 2017

An 18-year follow-up study of postmenopausal women in the Women’s Health Initiative trials has shown that the use of hormone therapy was not associated with any increased risk of all-cause, cardiovascular or cancer death.

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Hormone therapy is known to reduce menopausal symptoms such as hot flashes and to decrease the risk of bone fractures, but it has also been linked to an increased risk of blood clots, stroke and some cancers. Previous studies have reported health outcomes for women taking the therapy, but generally, they have not concentrated on all-cause or cause-specific mortality.

All-cause mortality provides a critically important summary measure for an intervention such as hormone therapy that has a complex matrix of benefits and risks... Mortality rates are the ultimate 'bottom line' when assessing the net effect of a medication on serious and life-threatening health outcomes."

JoAnn Manson, Brigham and Women's Hospital, Harvard Medical School, Boston

The trials tested the use of the most common formulations – estrogen plus progestin and estrogen alone versus the use of placebo among predominantly healthy menopausal women to assess the benefits and risks of taking the medication for chronic disease prevention. The women were aged between 50 and 79 years, with an average age of 63 years.

Taking data from the two trials, Manson and colleagues examined the effect of using the treatment over a five-to seven-year period and during 18-years of follow-up to define the impact hormone therapy had on all-cause and cause-specific death rates among 27,347 women.

During the 18-year follow-up, 7,489 deaths occurred. Of these deaths, 1,088 occurred during the treatment period and 6,401 during the post-intervention follow-up.

As reported in JAMA, when data were pooled for the overall cohort, all-cause death was 27.1% in the hormone therapy group, compared with 27.6% in the placebo group. The authors found that neither the use of estrogen plus progestin or estrogen alone was associated with any increase or decrease in risk for all-cause, cardiovascular or total cancer mortality.

The authors say the findings provide support for clinical guidelines endorsing the use of hormone therapy for recently menopausal women to manage bothersome hot flashes and other menopausal symptoms.