Two important considerations in clinical research studies are proper evaluations of internal and external validity. While randomized clinical trials can overcome several threats to internal validity, they may be prone to poor external validity. Conversely, large prospective observational studies sampled from a broadly generalizable population may be externally valid, yet susceptible to threats to internal validity, particularly confounding. Thus, methods that address confounding and enhance transportability of study results across populations are essential for internally and externally valid causal inference, respectively. These issues persist for another problem closely related to transportability known as data-fusion. We develop a calibration method to generate balancing weights that address confounding and sampling bias, thereby enabling valid estimation of the target population average treatment effect. We compare the calibration approach to two additional doubly-robust methods that estimate the effect of an intervention on an outcome within a second, possibly unrelated target population. The proposed methodologies can be extended to resolve data-fusion problems that seek to evaluate the effects of an intervention using data from two related studies sampled from different populations. A simulation study is conducted to demonstrate the advantages and similarities of the different techniques. We also test the performance of the calibration approach in a motivating real data example comparing whether the effect of biguanides versus sulfonylureas - the two most common oral diabetes medication classes for initial treatment - on all-cause mortality described in a historical cohort applied to a contemporary cohort of US Veterans with diabetes.
翻译:临床研究的两个重要考虑是对内部和外部有效性的适当评估。尽管随机临床试验可以克服对内部有效性的几种威胁,但可能会导致外部有效性差。相反,从广泛普遍人口抽样的大量未来观察研究可能具有外部有效性,但有可能对内部有效性造成威胁,特别是混乱。因此,解决不同人口之间研究结果的混乱和可转移性的方法对内部和外部有效因果关系的推断分别至关重要。这些问题对于与数据融合等可运输性密切相关的另一个问题依然存在。我们开发了一种平衡权重的校准方法,以解决相互纠结和抽样偏差,从而能够有效估计目标人口平均治疗效果。我们将校准方法与另外两种双紫色方法进行比较,以估计干预对第二个、可能无关的目标人口的结果的影响。拟议方法可以扩大,以解决试图利用从不同人口抽样的两份相关研究数据评价干预效果的数据融合问题。我们进行了模拟研究,以展示不同技术的优势和相似性,从而得以对目标人口平均治疗效果进行有效估计。我们还将校准方法与两次试验了对高度和高温等级进行初步分析的结果。我们还测试了对高温等级的等级的等级方法的实际效果。