Dataset Information

Coronary heart disease in postmenopausal recipients of estrogen plus progestin therapy: does the increased risk ever disappear? A randomized trial.

ABSTRACT:

Background

Estrogen plus progestin therapy increases the risk for coronary heart disease (CHD) in postmenopausal women. However, this increased risk might be limited to the first years of use and to women who start therapy late in menopause.

Objective

To estimate the effect of continuous estrogen plus progestin therapy on CHD risk over time and stratified by years since menopause.

Design

Women's Health Initiative randomized, double-blinded, placebo-controlled trial. (ClinicalTrials.gov registration number: NCT00000611)

Setting

40 U.S. clinical centers.

Patients

16 608 postmenopausal women with an intact uterus at baseline from 1993 to 1998.

Intervention

Conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d, or placebo.

Measurements

Adherence-adjusted hazard ratios and CHD-free survival curves estimated through inverse probability weighting.

Results

Compared with no use of hormone therapy, the hazard ratio for continuous use of estrogen plus progestin therapy was 2.36 (95% CI, 1.55 to 3.62) for the first 2 years and 1.69 (CI, 0.98 to 2.89) for the first 8 years. For women within 10 years after menopause, the hazard ratios were 1.29 (CI, 0.52 to 3.18) for the first 2 years and 0.64 (CI, 0.21 to 1.99) for the first 8 years, and the CHD-free survival curves for continuous use and no use of estrogen plus progestin crossed at about 6 years (CI, 2 years to 10 years).

Limitation

The analysis may not have fully adjusted for joint determinants of adherence and CHD risk. Sample sizes for some subgroup analyses were small.

Conclusion

No suggestion of a decreased risk for CHD was found within the first 2 years of estrogen plus progestin use, including in women who initiated therapy within 10 years after menopause. A possible cardioprotective effect in these women who initiated therapy closer to menopause became apparent only after 6 years of use.

Primary funding source

National Heart, Lung, and Blood Institute.

SUBMITTER: Toh S

PROVIDER: S-EPMC2936769 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:ContextIn the Women's Health Initiative randomized, placebo-controlled trial of estrogen plus progestin, after a mean intervention time of 5.6 (SD, 1.3) years (range, 3.7-8.6 years) and a mean follow-up of 7.9 (SD, 1.4) years, breast cancer incidence was increased among women who received combined hormone therapy. Breast cancer mortality among participants in the trial has not been previously reported.ObjectiveTo determine the effects of therapy with estrogen plus progestin on cumulative breast cancer incidence and mortality after a total mean follow-up of 11.0 (SD, 2.7) years, through August 14, 2009.Design, setting, and participantsA total of 16,608 postmenopausal women aged 50 to 79 years with no prior hysterectomy from 40 US clinical centers were randomly assigned to receive combined conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d, or placebo pill. After the original trial completion date (March 31, 2005), reconsent was required for continued follow-up for breast cancer incidence and was obtained from 12,788 (83%) of the surviving participants.Main outcome measuresInvasive breast cancer incidence and breast cancer mortality.ResultsIn intention-to-treat analyses including all randomized participants and censoring those not consenting to additional follow-up on March 31, 2005, estrogen plus progestin was associated with more invasive breast cancers compared with placebo (385 cases [0.42% per year] vs 293 cases [0.34% per year]; hazard ratio [HR], 1.25; 95% confidence interval [CI], 1.07-1.46; P = .004). Breast cancers in the estrogen-plus-progestin group were similar in histology and grade to breast cancers in the placebo group but were more likely to be node-positive (81 [23.7%] vs 43 [16.2%], respectively; HR, 1.78; 95% CI, 1.23-2.58; P = .03). There were more deaths directly attributed to breast cancer (25 deaths [0.03% per year] vs 12 deaths [0.01% per year]; HR, 1.96; 95% CI, 1.00-4.04; P = .049) as well as more deaths from all causes occurring after a breast cancer diagnosis (51 deaths [0.05% per year] vs 31 deaths [0.03% per year]; HR, 1.57; 95% CI, 1.01-2.48; P = .045) among women who received estrogen plus progestin compared with women in the placebo group.ConclusionsEstrogen plus progestin was associated with greater breast cancer incidence, and the cancers are more commonly node-positive. Breast cancer mortality also appears to be increased with combined use of estrogen plus progestin.Trial registrationclinicaltrials.gov Identifier: NCT00000611.

Project description:IMPORTANCE:The use of menopausal hormone therapy (HT) continues in clinical practice, but reports are conflicting concerning the longer-term breast cancer effects of relatively short-term use. OBJECTIVE:To report the longer-term influence of menopausal HT on breast cancer incidence in the 2 Women's Health Initiative (WHI) randomized clinical trials. DESIGN, SETTING, AND PARTICIPANTS:A total of 27,347 postmenopausal women aged 50 to 79 years were enrolled at 40 US centers from 1993 to 1998 and followed up for a median of 13 years through September 2010. INTERVENTIONS:A total of 16,608 women with a uterus were randomized to conjugated equine estrogens (0.625 mg/d [estrogen]) plus medroxyprogesterone acetate (2.5 mg/d [progestin]) (E?+?P) or placebo with a median intervention duration of 5.6 years, and 10,739 women with prior hysterectomy were randomized to conjugated equine estrogens alone (0.625 mg/d) or placebo with a median intervention duration of 7.2 years. MAIN OUTCOMES AND MEASURES:Time-specific invasive breast cancer incidence rates and exploratory analyses of breast cancer characteristics by intervention and postintervention phases in the 2 HT trials. RESULTS:In the E?+?P trial, hazard ratios (HRs) for the influence of combined HT on breast cancer were lower than 1 for 2 years (HR, 0.71; 95% CI, 0.47-1.08) and steadily increased throughout intervention, becoming significantly increased for the entire intervention phase (HR, 1.24; 95% CI, 1.01-1.53). In the early postintervention phase (within 2.75 years from intervention), there was a sharp decrease in breast cancer incidence in the combined HT group, though the HR remained higher than 1 (HR, 1.23; 95% CI, 0.90-1.70). During the late postintervention phase (requiring patient re-consent), the HR for breast cancer risk remained higher than 1 through 5.5 years (median) of additional follow-up (HR, 1.37; 95% CI, 1.06-1.77). In the estrogen alone trial, the HR for invasive breast cancer risk was lower than 1 throughout the intervention phase (HR, 0.79; 95% CI, 0.61-1.02) and remained lower than 1 in the early postintervention phase (HR, 0.55; 95% CI, 0.34-0.89), but risk reduction was not observed during the late postintervention follow-up (HR, 1.17; 95% CI, 0.73-1.87). Characteristics of breast cancers diagnosed during early and late postintervention phases differed in both trials. CONCLUSIONS AND RELEVANCE:In the E?+?P trial, the higher breast cancer risk seen during intervention was followed by a substantial drop in risk in the early postintervention phase, but a higher breast cancer risk remained during the late postintervention follow-up. In the estrogen alone trial, the lower breast cancer risk seen during intervention was sustained in the early postintervention phase but was not evident during the late postintervention follow-up.