Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results From the Women's Health Initiative randomized controlled trial.
BACKGROUND
Despite decades of accumulated observational evidence, the balance of risks and benefits for hormone use in healthy postmenopausal women remains uncertain.


OBJECTIVE
To assess the major health benefits and risks of the most commonly used combined hormone preparation in the United States.


METHODS
Estrogen plus progestin component of the Women's Health Initiative, a randomized controlled primary prevention trial (planned duration, 8.5 years) in which 16608 postmenopausal women aged 50-79 years with an intact uterus at baseline were recruited by 40 US clinical centers in 1993-1998.


METHODS
Participants received conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d, in 1 tablet (n = 8506) or placebo (n = 8102).


METHODS
The primary outcome was coronary heart disease (CHD) (nonfatal myocardial infarction and CHD death), with invasive breast cancer as the primary adverse outcome. A global index summarizing the balance of risks and benefits included the 2 primary outcomes plus stroke, pulmonary embolism (PE), endometrial cancer, colorectal cancer, hip fracture, and death due to other causes.


RESULTS
On May 31, 2002, after a mean of 5.2 years of follow-up, the data and safety monitoring board recommended stopping the trial of estrogen plus progestin vs placebo because the test statistic for invasive breast cancer exceeded the stopping boundary for this adverse effect and the global index statistic supported risks exceeding benefits. This report includes data on the major clinical outcomes through April 30, 2002. Estimated hazard ratios (HRs) (nominal 95% confidence intervals [CIs]) were as follows: CHD, 1.29 (1.02-1.63) with 286 cases; breast cancer, 1.26 (1.00-1.59) with 290 cases; stroke, 1.41 (1.07-1.85) with 212 cases; PE, 2.13 (1.39-3.25) with 101 cases; colorectal cancer, 0.63 (0.43-0.92) with 112 cases; endometrial cancer, 0.83 (0.47-1.47) with 47 cases; hip fracture, 0.66 (0.45-0.98) with 106 cases; and death due to other causes, 0.92 (0.74-1.14) with 331 cases. Corresponding HRs (nominal 95% CIs) for composite outcomes were 1.22 (1.09-1.36) for total cardiovascular disease (arterial and venous disease), 1.03 (0.90-1.17) for total cancer, 0.76 (0.69-0.85) for combined fractures, 0.98 (0.82-1.18) for total mortality, and 1.15 (1.03-1.28) for the global index. Absolute excess risks per 10 000 person-years attributable to estrogen plus progestin were 7 more CHD events, 8 more strokes, 8 more PEs, and 8 more invasive breast cancers, while absolute risk reductions per 10 000 person-years were 6 fewer colorectal cancers and 5 fewer hip fractures. The absolute excess risk of events included in the global index was 19 per 10 000 person-years.


CONCLUSIONS
Overall health risks exceeded benefits from use of combined estrogen plus progestin for an average 5.2-year follow-up among healthy postmenopausal US women. All-cause mortality was not affected during the trial. The risk-benefit profile found in this trial is not consistent with the requirements for a viable intervention for primary prevention of chronic diseases, and the results indicate that this regimen should not be initiated or continued for primary prevention of CHD.
Division of Women's Health Initiative, National Heart, Lung, and Blood Institute, 6705 Rockledge Dr, One Rockledge Ctr, Suite 300, Bethesda, MD 20817, USA.rossouw@nih.gov
Jacques E
JE
Rossouw
Garnet L
GL
Anderson
Ross L
RL
Prentice
Andrea Z
AZ
LaCroix
Charles
C
Kooperberg
Marcia L
ML
Stefanick
Rebecca D
RD
Jackson
Shirley A A
SA
Beresford
Barbara V
BV
Howard
Karen C
KC
Johnson
Jane Morley
JM
Kotchen
Judith
J
Ockene
D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D026661:Clinical Trials Data Monitoring Committees; D015179:Colorectal Neoplasms / Q000453:epidemiology; D003327:Coronary Disease / Q000453:epidemiology* / Q000517:prevention & control; D016889:Endometrial Neoplasms / Q000453:epidemiology; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D004966:Estrogens, Conjugated (USP) / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology / Q000517:prevention & control; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D017698:Postmenopause; D045167:Progesterone Congeners / Q000009:adverse effects / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D011655:Pulmonary Embolism / Q000453:epidemiology; D012306:Risk; D020521:Stroke / Q000453:epidemiology; D016019:Survival Analysis; D013927:Thrombosis / Q000453:epidemiology; D016896:Treatment Outcome
D004966:Estrogens, Conjugated (USP); D045167:Progesterone Congeners; D017258:Medroxyprogesterone Acetate