Background: Randomized controlled trials (RCT) play a central role in evidence-based healthcare. However, the clinical and policy implications of implementing RCTs in clinical practice are difficult to predict as the studied population is often different from the target population where results are being applied. This study illustrates the concepts of generalizability and transportability, demonstrating their utility in interpreting results from the National Lung Screening Trial (NLST). Methods: Using inverse-odds weighting, we demonstrate how generalizability and transportability techniques can be used to extrapolate treatment effect from (i) a subset of NLST to the entire NLST population and from (ii) the entire NLST to different target populations. Results: Our generalizability analysis revealed that lung cancer mortality reduction by LDCT screening across the entire NLST [16% (95% confidence interval [CI]: 4–24)] could have been estimated using a smaller subset of NLST participants. Using transportability analysis, we showed that populations with a higher prevalence of females and current smokers had a greater reduction in lung cancer mortality with LDCT screening [e.g., 27% (95% CI, 11–37) for the population with 80% females and 80% current smokers] than those with lower prevalence of females and current smokers. Conclusions: This article illustrates how generalizability and transportability methods extend estimation of RCTs' utility beyond trial participants, to external populations of interest, including those that more closely mirror real-world populations. Impact: Generalizability and transportability approaches can be used to quantify treatment effects for populations of interest, which may be used to design future trials or adjust lung cancer screening eligibility criteria.

中文翻译：

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国家肺筛查试验数据的普遍性和可转移性：将试验结果扩展到不同人群

背景：随机对照试验 (RCT) 在循证医疗保健中发挥着核心作用。然而，在临床实践中实施 RCT 的临床和政策影响难以预测，因为研究人群通常与应用结果的目标人群不同。这项研究说明了普遍性和可转移性的概念，证明了它们在解释国家肺筛查试验 (NLST) 的结果中的实用性。方法：使用逆优势加权，我们展示了如何使用泛化性和可迁移性技术将治疗效果从 (i) NLST 的一个子集外推到整个 NLST 人群，以及从 (ii) 整个 NLST 到不同的目标人群。结果：我们的普遍性分析表明，LDCT 筛查在整个 NLST 中降低了肺癌死亡率 [16%（95% 置信区间 [CI]：4-24）] 可以使用较小的 NLST 参与者子集进行估计。使用可转移性分析，我们发现女性和当前吸烟者患病率较高的人群在接受 LDCT 筛查时肺癌死亡率降低幅度更大[例如，对于 80% 女性和80% 当前吸烟者] 比女性和当前吸烟者的患病率低。结论：本文说明了普遍性和可转移性方法如何将 RCT 效用的估计扩展到试验参与者之外，扩展到感兴趣的外部人群，包括那些更接近真实世界人群的人群。影响：