Background:

Restricted mean survival time methods compare the areas under the Kaplan–Meier curves up to a time $\tau$ for the control and experimental treatments. Extraordinary claims have been made about the benefits (in terms of dramatically smaller required sample sizes) when using restricted mean survival time methods as compared to proportional hazards methods for analyzing noninferiority trials, even when the true survival distributions satisfy proportional hazardss.

Methods:

Through some limited simulations and asymptotic power calculations, the authors compare the operating characteristics of restricted mean survival time and proportional hazards methods for analyzing both noninferiority and superiority trials under proportional hazardss to understand what relative power benefits there are when using restricted mean survival time methods for noninferiority testing.

Results:

In the setting of low-event rates, very large targeted noninferiority margins, and limited follow-up past $\tau$, restricted mean survival time methods have more power than proportional hazards methods. For superiority testing, proportional hazards methods have more power. This is not a small-sample phenomenon but requires a low-event rate and a large noninferiority margin.

Conclusion:

Although there are special settings where restricted mean survival time methods have a power advantage over proportional hazards methods for testing noninferiority, the larger issue in these settings is defining appropriate noninferiority margins. We find the restricted mean survival time methods lacking in these regards.

中文翻译：

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限制平均生存时间方法对非劣效性试验特别有用吗？

背景：

受限平均生存时间方法比较 Kaplan-Meier 曲线下的面积 $\tau$用于对照和实验处理。与分析非劣效性试验的比例风险方法相比，即使真实生存分布满足比例风险，使用受限平均生存时间方法的好处（就所需样本量显着减少而言）也有非凡的主张。

方法：

通过一些有限的模拟和渐近功效计算，作者比较了受限平均生存时间和比例风险方法的操作特性，以分析比例风险下的非劣效性和优效性试验，以了解使用受限平均生存时间方法时的相对功效优势。非劣效性检验。

结果：

在低事件发生率、非常大的目标非劣效性边界和有限的过去随访的情况下 $\tau$, 受限平均生存时间方法比比例风险方法具有更大的功效。对于优势测试，比例风险方法具有更大的功效。这不是小样本现象，而是需要低事件率和大的非劣效性余量。

结论：

尽管在某些特殊情况下，限制平均生存时间方法在检验非劣效性时比比例风险方法具有功效优势，但这些设置中更大的问题是定义适当的非劣效性界限。我们发现在这些方面缺乏限制平均生存时间方法。