Signorello Lisa B, McLaughlin Joseph K, Lipworth Loren, Friis Søren, Sørensen Henrik Toft, Blot William J
International Epidemiology Institute, Rockville, Maryland, USA; Department of Medicine, Vanderbilt University Medical Center, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, USA.
Am J Ther. 2002 May-Jun;9(3):199-205. doi: 10.1097/00045391-200205000-00005.
Confounding by indication is a bias frequently encountered in observational epidemiologic studies of drug effects. Because the allocation of treatment in observational studies is not randomized and the indication for treatment may be related to the risk of future health outcomes, the resulting imbalance in the underlying risk profile between treated and comparison groups can generate biased results. Confounding by indication is often present in studies of drugs that are not widely prescribed, because the indications for their use are narrow and not likely to be present in comparison groups; however, this bias is also observed in the study of widely used over-the-counter and prescription drugs, are exemplified by studies of analgesics. In this article we review examples from the published literature to demonstrate how confounding by indication can affect the findings of pharmacoepidemiologic studies relating analgesic use to various health outcomes.
适应症混杂是药物效应观察性流行病学研究中经常遇到的一种偏倚。由于观察性研究中的治疗分配并非随机进行，且治疗指征可能与未来健康结局的风险相关，因此治疗组和对照组之间潜在风险特征的失衡可能会产生有偏的结果。适应症混杂在未广泛处方药物的研究中经常出现，因为其使用指征狭窄，对照组中不太可能存在；然而，这种偏倚在广泛使用的非处方药和处方药研究中也有观察到，以镇痛药研究为例。在本文中，我们回顾已发表文献中的实例，以说明适应症混杂如何影响将镇痛药使用与各种健康结局相关联的药物流行病学研究的结果。
