METHODS

Design:

2 randomised placebo-controlled trials (Women’s Health Initiative [WHI] trials).

Allocation:

{concealed}*.†

Blinding:

blinded {clinicians, participants, data collectors, outcome assessors, and monitoring committee}*.†

Follow-up period:

mean 5.6‡ and 7.1§ years.

Setting:

40 US clinical centres.

Participants:

27 347 predominantly healthy postmenopausal women 50–79 years of age (mean age 63* and 64|| y).

Intervention

conjugated equine oestrogen (CEO), 0.625 mg/day, plus medroxyprogesterone acetate, 2.5 mg/day (n = 8506), or placebo (n = 8102) in women with an intact uterus; CEO, 0.625 mg/day (n = 5310), or placebo (n = 5429) in women with a hysterectomy.

Outcomes:

coronary heart disease (CHD) (myocardial infarction or CHD death), stroke, total mortality, and a global index.

Participant follow-up:

94%‡|| (intention-to-treat analysis).

MAIN RESULTS

Overall, the HT and placebo groups did not differ for CHD, total mortality, and the global index; the risk of stroke was higher in the HT group …