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- coronary disease
- oestrogens (conjugated)
- hormone replacement therapy
- medroxyprogesterone 17-acetate
- progestational hormones (synthetic)
Q In postmenopausal women, how does oestrogen plus progestogen influence the risk of coronary heart disease (CHD)?
Clinical impact ratings GP/FP/Primary care ★★★★★☆☆ IM/Ambulatory care ★★★★★☆☆ Endocrine ★★★★★☆☆ Cardiology ★★★★★☆☆
METHODS
Design:
randomised placebo controlled trial.
Allocation:
Blinding:
blinded (clinicians, participants, data collectors, outcome assessors, and monitoring committee).†
Follow up period:
5.6 years (Women’s Health Initiative [WHI]).
Setting:
{40 US clinical centres}*.
Patients:
16 608 postmenopausal women who were 50–79 years of age (mean age 63 y), had an intact uterus, and resided in the same geographic area for ⩾3 years.
Interventions:
patients were allocated to oral conjugated equine oestrogen, 0.625 mg/day, plus medroxyprogesterone acetate, 2.5 mg/day (n = 8506), or placebo (n = 8102).
Outcomes:
CHD (ie, acute myocardial infarction [MI] requiring overnight hospital admission; death caused by CHD; or silent MI. Secondary outcomes: coronary revascularisation, angina, and congestive heart failure.
Patient follow up:
94%.
MAIN RESULTS
Analysis was by intention to treat. Patients who received oestrogen plus progestogen had a greater risk of CHD during the first year (hazard ratio 1.81, 95% CI 1.09 to 3.01). The groups did not differ for CHD risk by the end of follow up or for any other CHD outcomes (table).
Oestrogen plus progestogen v placebo (HT) for incidence of coronary heart disease (CHD) in postmenopausal women at mean 5.6 years*
CONCLUSIONS
Postmenopausal women were at increased risk of coronary heart disease (CHD) during the first year of hormone therapy. Risk of CHD was not reduced during longer follow up.
Abstract and commentary also appear in ACP Journal Club.
Commentary
The study by Manson et al updates previous WHI data and provides information on additional clinical endpoints. Although CHD rates were higher in women who received hormone therapy (HT) than in women who received placebo, the conservative 95% CIs for CHD and other outcomes each overlapped 1 after adjustment for sequential monitoring and multiple outcomes. In addition, coronary risk factor status was not significantly associated with the risk of CHD for those taking HT. The high rate of discontinuation of HT (42%) and placebo (38%) suggests that the adverse effects of HT may have been underestimated.
Why does this and other randomised trials contradict previous observational studies, which showed a benefit of HT for CHD? Menopausal women who choose to take HT are more likely to be well educated and have lower cardiovascular risk (eg, lower blood pressure, weight, glucose, and cholesterol) than women who are not taking oestrogen.1,2 Because of baseline differences between users and nonusers of HT, randomisation in the WHI study revealed the potential for an increase in CHD risk attributable to HT that was not apparent in observational studies. As the investigators point out, differences in age and years since menopause, as well as methodological limitations of observational studies, may have perpetuated incorrect impressions. The hypothesis that the timing of HT in these women was too late to halt an already irrevocable atherosclerotic process seems unlikely.
Several important questions remain. Will we find a way to predict which HT users will have increased CHD risk? What are the risks and benefits for women with current menopause symptoms (which was not the focus of WHI)? Considering the current state of evidence, clinicians cannot use coronary risk factor status to predict CHD risk associated with HT use and should integrate the possibility of adverse cardiovascular consequences (although uncommon) into their counselling for women who are starting HT.
Footnotes
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↵*
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For correspondence: Dr J E Manson, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA. jmansonrics.bwh.harvard.edu
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Source of funding: National Heart, Lung and Blood Institute.
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