Background: The findings of the Women's Health Initiative (WHI) estrogen plus progestin (E+P) trial led to a substantial reduction in use of combined hormone therapy (cHT) among postmenopausal women in the United States. The economic effect of this shift has not been evaluated relative to the trial's $260 million cost (2012 U.S. dollars).
Objective: To estimate the economic return from the WHI E+P trial.
Design: Decision model to simulate health outcomes for a “WHI scenario” with observed cHT use and a “no-WHI scenario” with cHT use extrapolated from the pretrial period.
Data Sources: Primary analyses of WHI outcomes, peer-reviewed literature, and government sources.
Target Population: Postmenopausal women in the United States, aged 50 to 79 years, who did not have a hysterectomy.
Time Horizon: 2003 to 2012.
Intervention: Combined hormone therapy.
Outcome Measures: Disease incidence, expenditure, quality-adjusted life-years, and net economic return.
Results of Base-Case Analysis: The WHI scenario resulted in 4.3 million fewer cHT users, 126 000 fewer breast cancer cases, 76 000 fewer cardiovascular disease cases, 263 000 more fractures, 145 000 more quality-adjusted life-years, and expenditure savings of $35.2 billion. The corresponding net economic return of the trial was $37.1 billion ($140 per dollar invested in the trial) at a willingness-to-pay level of $100 000 per quality-adjusted life-year.
Results of Sensitivity Analysis: The 95% CI for the net economic return of the trial was $23.1 to $51.2 billion.
Limitation: No evaluation of indirect costs or outcomes beyond 2012.
Conclusion: The WHI E+P trial made high-value use of public funds with a substantial return on investment. These results can contribute to discussions about the role of public funding for large, prospective trials with high potential for public health effects.
Primary Funding Source: National Heart, Lung, and Blood Institute.