Hasegawa Takahiro
Biostatistics Center, Shionogi & Co., Ltd.
Gan To Kagaku Ryoho. 2022 Apr;49(4):389-396.
Many clinical research and studies evaluate a time-to-event data, illustrate survival curves, and conventionally report an estimated hazard ratio to express the magnitude of the treatment effect when comparing between groups. However, it may not be straightforward to interpret the hazard ratio clinically and statistically when the proportional hazards assumption is invalid. In some recent papers published in clinical journals, the use of restricted mean survival time(RMST)or t-year mean survival time is discussed as one of the alternative summary measures for the time-to-event data. The RMST is defined as the expected value of time-to-event limited to a specific time point corresponding to the area under the survival curve up to the specific time point. This article summarizes the necessary information to conduct statistical analysis using the RMST, including the definition and statistical properties of the RMST, and clinical and statistical meaning and interpretation as compared with other summary measures of time-to-event data by application examples.
许多临床研究评估事件发生时间数据，绘制生存曲线，并在比较组间差异时，传统地报告估计的风险比以表达治疗效果的大小。然而，当比例风险假设无效时，从临床和统计学角度解释风险比可能并非易事。在临床期刊最近发表的一些论文中，讨论了使用受限平均生存时间（RMST）或t年平均生存时间作为事件发生时间数据的替代汇总指标之一。RMST被定义为事件发生时间的期望值，其限制在与生存曲线下直至特定时间点的面积相对应的特定时间点。本文总结了使用RMST进行统计分析所需的信息，包括RMST的定义和统计特性，以及通过应用实例与事件发生时间数据的其他汇总指标相比的临床和统计意义及解释。
