Background: The effects of hormone therapy (HT) on incidence and outcomes of heart failure (HF) in women are unknown. We compared the incidence of HF and survival after diagnosis in post-menopausal women age 50 –79 years randomized to 0.625 mg daily of conjugated equine estrogen (CEE) alone or in combination with 2.5 mg daily of medroxyprogesterone acetate (MPA) or placebo (PLC), as part of the Women’s Health Initiative (WHI) HT trials.
Methods: A total of 10,739 women with prior hysterectomy were randomized to CEE or PLC and 16,608 women with uterus were randomized to CEE+MPA or PLC. Potential HF events were identified via participant self-report during semiannual contact or via adjudication of another primary outcome. Events were reviewed and adjudicated by 3 cardiologists and standardized HF clinical and radiographic criteria (Framingham and WHI) were applied. Multivariable Cox models were used to compare HF incidence and subsequent cardiovascular disease (CVD) and all-cause mortality between treatment groups.
Results: After a mean follow-up of 7.9 years, 331 incident HF events occurred (incidence rate 1.6 per 1,000 person-years). The risk of HF was not significantly different in the combined HT compared to PLC group (Table). The HR in individual HT arms were similar (Table). Results were similar across baseline ages in age-stratified analyses. There were 61 CVD deaths (incidence rate 62 per 1,000 person-years) and 95 total deaths (incidence rate 97 per 1,000 person-years) in women with incident HF, and 339 CVD deaths (incidence rate 2 per 1,000 person-years) and 1307 total deaths (incidence rate 6 per 1,000 person-years) in women with no HF. In the combined trials, HT had no effect on survival: HR 0.85 (95% CI 0.5–1.4) for CVD mortality and 1.04 (95% CI 0.7–1.6) for all-cause mortality.
Conclusions: The incidence of HF in generally healthy post-menopausal women is low. Treatment with CEE or CEE+MPA does not protect against HF, nor improve survival in older women who develop HF.