Quantifying bias reduction with fixed-duration versus all-available covariate assessment periods
Quantifying bias reduction with fixed-duration versus all-available covariate assessment periods
复制标题
DOI：
10.1002/pds.4729
复制
发表时间：
2019-05-01
影响因子：
2.6
通讯作者：
Gagne, Joshua J.
中科院分区：
文献类型：
--
作者：
Connolly, John G.;Schneeweiss, Sebastian;Gagne, Joshua J.
目的：在纵向健康保健数据库中实施队列研究需要回顾队列输入之前的一些协变量评估期(CAP)，以测量混杂因素。我们使用模拟来比较在暴露组之间存在可用基线时间差异的情况下用于混杂因素调整的固定持续时间和所有可用的上限。方法：我们模拟了具有单一混杂因素、暴露和结果的二元变量的10000名患者的队列。基线时间是根据他汀类药物使用者和非使用者基于声明的比较中观察到的分布来模拟的。我们比较了使用固定持续时间和所有可用上限测量混杂因素后的偏差，这两种情况下暴露组具有相似和不同的可用基线时间。结果：当对照组具有相似的基线时间时，所有可用CAP比固定持续时间CAP的偏差更小。当基线时间在对照组之间不同时，更好的CAP方法取决于混淆的方向以及哪一暴露组具有更高的协变量敏感性。在敏感性分析中，这些发现在方向上是一致的。结论：在暴露组之间不同的可用基线时间的某些设置下，所有可用的CAP比固定持续时间的CAP更有偏见。在选择固定期限或所有可用的CAP时，混淆和错误分类偏差的相对方向和强度是一个重要的考虑因素，但它们往往是未知的。因此，我们建议比较不同暴露组之间的可用基线时间。当存在较大差异时，尽管选择了适当的设计，我们仍建议采用固定持续时间的方法，以避免因数据可用性不同而可能导致的偏差增加。
Purpose: Implementing a cohort study in longitudinal healthcare databases requires looking back over some covariate assessment period (CAP) preceding cohort entry to measure confounders. We used simulations to compare fixed-duration versus all-available CAPs for confounder adjustment in the presence of differences in available baseline time between exposure groups.Methods: We simulated cohorts of 10 000 patients with binary variables for a single confounder, exposure, and outcome. Baseline time was simulated based on the observed distribution in a claims-based comparison of statin users versus nonusers. We compared bias after measuring confounders using fixed-duration and all-available CAPs, both when exposure groups had similar and discrepant amounts of available baseline time.Results: When the comparison groups had similar amounts of baseline time, an all-available CAP was less biased than a fixed-duration CAP. When baseline time differed between comparison groups, the preferable CAP approach depended on the direction of confounding and which exposure group had higher covariate sensitivity. These findings were consistent in direction across sensitivity analyses.Conclusion: In certain settings of differential available baseline time between exposure groups, the all-available CAP was more biased than the fixed-duration CAP. The relative directions and strengths of confounding and misclassification biases are an important consideration when choosing between a fixed-duration or all-available CAP, but they are often unknown. Therefore, we recommend comparing the amount of available baseline time between exposure groups. When there is a large discrepancy, despite appropriate design choices, we recommend a fixed-duration approach to avoid potential increases in bias because of differential data availability.