The self-controlled case series method is one of two approaches used to estimate the association between covid-19 and venous thromboembolism or bleeding. This article briefly describes the method, its assumptions, and how it was implemented in the linked study, and offers some pointers to guide the interpretation of the results. The self-controlled case series method is an epidemiological design for estimating the association between an exposure and a health outcome.12 In the linked study (doi:10.1136/bmj-2021-069590), the exposure is covid-19 and the outcome is deep vein thrombosis, pulmonary embolism, or bleeding.3 The self-controlled case series method automatically adjusts for all multiplicative confounders that do not vary over the duration of the study—automatically meaning that such confounders need not be adjusted for explicitly measured, or even known. This is because estimation is within individuals: individuals act as their own control (hence the term self-controlled). Time varying confounders (such as time, age, or other exposures), however, must be adjusted for explicitly. Also, cases (people who have experienced the outcome) only need be sampled as they contribute to the estimation (hence the term case series). For these reasons, the method is well suited to the analysis …

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自控病例系列方法和covid-19

自控病例系列方法是用于估计 covid-19 与静脉血栓栓塞或出血之间关联的两种方法之一。本文简要介绍了该方法、其假设以及如何在关联研究中实施，并提供一些指导来指导结果的解释。自控病例系列方法是一种流行病学设计，用于估计暴露与健康结果之间的关联。 12 在关联研究 (doi:10.1136/bmj-2021-069590) 中，暴露为 covid-19，结果为深静脉血栓形成、肺栓塞或出血。 3 自控病例系列方法自动调整所有在研究期间不变的乘法混杂因素——自动意味着此类混杂因素无需针对明确测量进行调整，甚至已知。这是因为估计在个人内部：个人作为自己的控制（因此称为自我控制）。但是，必须明确调整时变混杂因素（例如时间、年龄或其他暴露）。此外，案例（经历过结果的人）只需要抽样，因为它们有助于估计（因此称为案例系列）。由于这些原因，该方法非常适合分析……