Angrist Joshua, Kowalski Amanda E, Ristovska Ljubica, Stefanick Marcia L
Massachusetts Institute of Technology.
University of Michigan.
AEA Pap Proc. 2025 May;115:215-220. doi: 10.1257/pandp.20251064.
Landmark results from the Women's Health Initiative trial showed that random assignment to menopausal hormone therapy (MHT) elevated risks of breast cancer and other adverse events. Recent analyses argue that MHT risks are small. These analyses report intention-to-treat (ITT) effects, ignoring the fact that many women assigned intervention were non-adherent, while many women assigned control initiated treatment. Instrumental variable (IV) methods and adherence data allow us to estimate effects of MHT on compliers who took MHT if and only if assigned. IV estimates show risks and benefits that are substantially larger than the ITT estimates used to inform MHT guidelines.
妇女健康倡议试验的标志性结果表明，随机分配接受绝经激素治疗（MHT）会增加患乳腺癌和其他不良事件的风险。最近的分析认为MHT的风险很小。这些分析报告的是意向性治疗（ITT）效应，却忽略了一个事实，即许多被分配接受干预的女性并未坚持治疗，而许多被分配为对照组的女性却开始了治疗。工具变量（IV）方法和依从性数据使我们能够估计MHT对那些只有在被分配的情况下才会服用MHT的依从者的影响。IV估计显示的风险和益处比用于制定MHT指南的ITT估计要大得多。
