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Instrumental variable methods in comparative safety and effectiveness research
Author(s) -
Brookhart M. Alan,
Rassen Jeremy A.,
Schneeweiss Sebastian
Publication year - 2010
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.1908
Subject(s) - instrumental variable , medicine , confounding , pharmacoepidemiology , comparative effectiveness research , estimation , variable (mathematics) , management science , outcome (game theory) , risk analysis (engineering) , perspective (graphical) , psychological intervention , research design , clinical study design , computer science , econometrics , clinical trial , alternative medicine , machine learning , statistics , artificial intelligence , pharmacology , psychiatry , mathematics , mathematical analysis , management , mathematical economics , pathology , medical prescription , economics
Instrumental variable (IV) methods have been proposed as a potential approach to the common problem of uncontrolled confounding in comparative studies of medical interventions, but IV methods are unfamiliar to many researchers. The goal of this article is to provide a non‐technical, practical introduction to IV methods for comparative safety and effectiveness research. We outline the principles and basic assumptions necessary for valid IV estimation, discuss how to interpret the results of an IV study, provide a review of instruments that have been used in comparative effectiveness research, and suggest some minimal reporting standards for an IV analysis. Finally, we offer our perspective of the role of IV estimation vis‐à‐vis more traditional approaches based on statistical modeling of the exposure or outcome. We anticipate that IV methods will be often underpowered for drug safety studies of very rare outcomes, but may be potentially useful in studies of intended effects where uncontrolled confounding may be substantial. Copyright © 2010 John Wiley & Sons, Ltd.