Institute:Office of National Coordinator (ONC) Workforce Training Curriculum
Component:The Culture of Health Care
Unit:Evidence-Based Practice
Lecture:Phrasing the clinical question
Interventions
Slide content:Examples of RCTs Womens Health Initiative (WHI) Previous non-RCT studies suggested women who used postmenopausal hormone replacement therapy (HRT) at any time had lower mortality overall and from heart disease In general, RCTs and observational studies had yielded conflicting results WHI study was RCT that settled the issue (Writing Group for the Women's Health Initiative Investigators, 2002; Lowe, 2002), showing no benefit and possible harm from increased risk of breast cancer and cardiovascular disease Observational studies found to be confounded by non-similarities between users and non-users (Humphrey, Chan, & Sox, 2002) 12
Slide notes:Lets look at some examples of RCTs. A number of well-known RCTs come from the Womens Health Initiative, or WHI [W-H-I]. Before the publication of the WHI RCTs, there were many previous non-randomized controlled studies that suggested women who at any time had used postmenopausal hormone replacement therapy, or HRT [H-R-T], which is an estrogen and/or progesterone regimen after menopause, had lower mortality overall and lower mortality from heart disease. In general, RCTs and observational studies had yielded conflicting results. The original WHI study was the RCT that settled the issue, showing that HRT provided not only no benefit but also possible harm from increased risk of breast cancer and cardiovascular disease. Further analysis of the previous observational studies found that they were confounded by non-similarities among users and non-users. For example, women of higher socioeconomic status, who were in general healthier, were more likely to use HRT. When these differences were controlled for, the benefit of HRT was no longer seen. 12