a consequence, the HT study pills were stopped in July 2002, with an average follow-up period of 5.2 years. The unopposed estrogen trial was halted in February 2004, after an average follow-up period of 6.8 years, on the basis that unopposed estrogen did not appear to affect the risk of heart disease, the primary outcome, which was in contrast to the findings of previous observational studies. On the other hand, there were indications for an increased risk of stroke. Unopposed estrogen did reduce the risk for osteoporotic fractures and, unlike the estrogen/progestin treatment, showed a decrease in breast cancer risk. As a consequence of the findings, which indicated that the incurred risks of HT outweigh the identified benefits, the study authors recommended that HT not be prescribed for the purpose of chronic disease prevention in postmenopausal women. The hypothesized and observed risks of specific clinical outcomes are summarized in the following table. Of particular interest are the contrasts between several of the hypothesized risks and the observed attributable risks, which are instructive in demonstrating the distinct differences between the HT trial findings and those of previous observational studies. Of all the WHI study findings, the HT findings could be argued to have yielded the farthest-reaching societal and economic impacts, and received substantial media attention. Large reductions in HT prescriptions ensued, resulting in a substantial loss of revenue in sales of this class of drugs, with a presumably commensurate savings to patients and insurers. More importantly, in subsequent years, studies have shown a decrease in breast cancer rates in postmenopausal women, attributed to the decline in use of HT. In 2014, an analysis was conducted to determine the economic impact of the estrogen-plus-progestin trial findings, which calculated the net economic return on investment to be $37.1 billion, owing to a combination of averted health-related expenditures and increased number of quality-adjusted life years (QALYs). The United States Preventive Services Task Force, though initially endorsing hormone replacement, in their most recent published recommendation in 2017 discouraged its use for the prevention of chronic diseases such as osteoporosis or cardiovascular disease. When they first evaluated the impact of HRT in 1996, the USPSTF assigned a "B" grade to hormone replacement therapy for use in primary prevention of chronic conditions in postmenopausal women, basing their results on observational studies and short-term trials. A score of "B" carries an official message of, "The USPSTF recommends the