Hormone therapy started near menopause was linked to lower cardiovascular risk in women with hot flushes

Design

Target-trial emulation using the SWAN prospective cohort

Population

2,737 perimenopausal or recently postmenopausal women with vasomotor symptoms

Primary outcome

Fatal and non-fatal cardiovascular events

Effect

aHR 0.78 (95% CI 0.62–0.98); within 10 years of menopause 0.73 (0.58–0.93)

Using 20 years of data from the multiethnic SWAN cohort, researchers emulated a series of trials of menopausal hormone therapy in 2,737 women with vasomotor symptoms and no cardiovascular disease; 755 started therapy and 224 cardiovascular events occurred.

Starting hormone therapy was associated with a lower risk of cardiovascular events overall (adjusted HR 0.78, 95% CI 0.62–0.98). The association held for women starting within 10 years of menopause (aHR 0.73) but not later (aHR 1.53, 0.66–3.52). It was strongest in Black women.

The authors are explicit that residual confounding is possible and that the results should not be used to prescribe hormone therapy for cardiovascular prevention. The practical point is narrower: for a woman in her early fifties with troublesome flushes, cardiovascular fear need not be the reason to withhold treatment.

• Treat troublesome vasomotor symptoms on their own merits; cardiovascular fear alone is not a reason to refuse
• Timing matters — the association was seen only when therapy began within 10 years of menopause
• Do not prescribe hormone therapy to prevent heart disease
• Assess breast cancer, venous thromboembolism and stroke risk before starting

Why it matters

It weakens a common reason symptomatic women in their fifties are kept off effective treatment.

Don't overread it

This was an observational emulation with possible residual confounding; it does not show hormone therapy prevents heart disease.

The statistics, in plain English

A target-trial emulation uses observational data to mimic the structure of a randomised trial, which reduces some biases but cannot remove confounding by who chooses treatment. The confidence interval for later starters, 0.66 to 3.52, is too wide to say anything either way.

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