What can we learn from design faults in the Women's Health Initiative randomized clinical trial?

Abstract

Design faults resulted in the inability of the Women's Health Initiative (WHI) randomized clinical trial to test the level of cardioprotection conferred by timely hormone treatment of women seeking help for menopausal complaints. Adopting a design constructed around the avoidance of symptomatic subjects and recruitment of older subjects who were more likely to manifest cardiovascular events during the life of the WHI resulted in recruitment of older, sicker subjects than are normally treated for complaints around the time of menopause. The lack of cardioprotection in subjects that began treatment a decade or more after menopause diluted cardioprotection in subjects starting treatment close to the menopausal transition. As a result, despite having the largest number of subjects ever, there were not enough women in the WHI who were comparable to those in the observational trials that showed cardioprotection. This led the WHI to report that there was no cardioprotection in the trial, a position that has been qualified after further analysis. Misapprehension of the initial WHI conclusions by the media, professionals, and regulatory agencies led to a major shift away from menopausal hormone treatment. This remains problematic since the evidence continues to favor cardioprotection and other benefits that are denied under present regulations and guidelines. Regulatory agencies and professional organizations need to better understand the faws in the WHI design and results in order to properly consider its results and the sustainability of their earlier conclusions and recommendations. Additionally, new trials are needed to test the validity of menopausal hormone-related cardioprotection.