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News Release

Health and financial analysis reinforces NIH's decision to fund Women's Health Initiative

An in-depth analysis of final data from one of the Women’s Health Initiative (WHI) Postmenopausal Hormone Therapy Trials has found that the investment in WHI resulted in a return of $140 in net economic value for each dollar invested in the trial.

The WHI, sponsored by the National Institutes of Health’s National Heart, Lung, and Blood Institute (NHLBI), has followed women in the study since 1993. Results of the trial of estrogen plus progestin were published in 2002. A paper examining the national post-study long-term financial and health outcomes of the WHI was published today in the Annals of Internal Medicine.

“I’m delighted to see these results from the WHI Postmenopausal Hormone Therapy Trial,” said NIH Director Francis S. Collins, M.D., Ph.D. “Americans should be pleased to see that their investment in NIH continues to provide such a strong return to their health and the economy.”

In assessing return on investment, the researchers looked at disease incidence, direct medical expenditure, quality-adjusted life years (a measure of disease burden, including quality and length of life), and net economic return between 2003 and 2012. The researchers’ analysis was based on a disease simulation model that used an estimate of approximately 39.1 million combined hormone therapy-eligible women between 2003 and 2012. The analysis found that the guidance provided by the WHI clinical trial results led to:

  • 76,000 fewer cases of cardiovascular disease (coronary heart disease, coronary artery bypass graft/percutaneous transluminal coronary angioplasty, and stroke)
  • 4.3 million fewer combined hormone therapy users
  • 126,000 fewer breast cancer cases
  • 145,000 more quality-adjusted life years
  • direct medical expenditure savings of 35.2 billion

While most of the results were positive, the analysis did find that the guidance provided by the WHI clinical trial results led to 263,000 more fractures (hip, vertebral, and other osteoporotic).

The researchers calculated the total net economic return of the trial, which cost $260 million in inflation-adjusted dollars, at $37.1 billion.

“The Women’s Health Initiative is a landmark study that has had a huge impact on medical practice and public health,” said NHLBI Director Gary H. Gibbons, M.D. “Even though the hormone therapy trial results were published more than 10 years ago, we are still learning from the women in the cohort. We anticipate that the quality of life return on investment will increase further as researchers continue to mine the data collected to uncover even more knowledge about hormone therapy and cardiovascular disease.”

Researchers compared actual observed combined hormone therapy use with a contrasting scenario based on the idea that the WHI trial had not been conducted. The net economic return of the trial was calculated as the difference in net economic value between the scenarios, less the trial cost.

The Women’s Health Initiative Hormone Trials studied 27,347 U.S. women ages 50-79 who enrolled in 1993 and 1998. There were 16,608 women with an intact uterus in the trial of estrogen plus progestin and 10,739 without a uterus in the trial of estrogen-alone. Women with an intact uterus were enrolled in the estrogen plus progestin trial because of the need to add progestin to the therapy to protect against endometrial cancer.

To schedule an interview with an NHLBI spokesperson, contact the NHLBI Communications Office at 301-496-4236 or


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