Reappraisal of Ventilator-Free Days in Critical Care Research
Reappraisal of Ventilator-Free Days in Critical Care Research
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DOI：
10.1164/rccm.201810-2050cp
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发表时间：
2019-10-01
影响因子：
24.7
通讯作者：
Reeder, Ron W.
中科院分区：
文献类型：
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作者：
Yehya, Nadir;Harhay, Michael O.;Reeder, Ron W.
无呼吸机天数（VFD）是急性呼吸窘迫综合征试验中常见的复合结局指标。VFD以总结干预对这两种结局的“净效应”的方式结合了联合收割机生存率和通气持续时间。然而，这种结果测量的组合使得VFD难以理解和分析，这导致不精确的解释。我们讨论了VFD和其他“无故障日”复合材料的优势和局限性，我们提供了一个框架，何时以及如何使用这些结果的措施。我们还提供了一个全面的讨论不同的分析方法来分析和解释VFD，包括学生的t检验和秩和检验，以及竞争风险回归治疗拔管的主要结果和死亡的竞争风险。使用模拟，我们说明了如何统计检验与最佳功率取决于死亡率和呼吸机持续时间的复合效应大小的相对贡献。最后，我们建议使用竞争风险方法建立一个简单的分析和报告框架，该框架提供有关干预措施效果大小的明确信息、统计检验和信心衡量标准，并能够调整基线因素并允许对试验进行中期监测。我们强调，任何分析综合结果的方法，包括其他“无故障日”结构，也应该伴随着对组成部分的检查。
Ventilator-free days (VFDs) are a commonly reported composite outcome measure in acute respiratory distress syndrome trials. VFDs combine survival and duration of ventilation in a manner that summarizes the "net effect" of an intervention on these two outcomes. However, this combining of outcome measures makes VFDs difficult to understand and analyze, which contributes to imprecise interpretations. We discuss the strengths and limitations of VFDs and other "failure-free day" composites, and we provide a framework for when and how to use these outcome measures. We also provide a comprehensive discussion of the different analytic methods for analyzing and interpreting VFDs, including Student's t tests and rank-sum tests, as well as competing risk regressions treating extubation as the primary outcome and death as the competing risk. Using simulations, we illustrate how the statistical test with optimal power depends on the relative contributions of mortality and ventilator duration on the composite effect size. Finally, we recommend a simple analysis and reporting framework using the competing risk approach, which provides clear information on the effect size of an intervention, a statistical test and measure of confidence with the ability to adjust for baseline factors and allow interim monitoring for trials. We emphasize that any approach to analyzing a composite outcome, including other "failure-free day" constructs, should also be accompanied by an examination of the components.