Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score

The prognostic score, or disease risk score (DRS), is a summary score that is used to control for confounding in non-experimental studies. While the DRS has been shown to effectively control for measured confounders, unmeasured confounding continues to be a fundamental obstacle in non-experimental r...

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Main Authors: Wyss Richard, Lunt Mark, Brookhart M. Alan, Glynn Robert J., Stürmer Til
Format: Article
Language:English
Published: De Gruyter 2014-09-01
Series:Journal of Causal Inference
Subjects:
Online Access:https://doi.org/10.1515/jci-2014-0009
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author Wyss Richard
Lunt Mark
Brookhart M. Alan
Glynn Robert J.
Stürmer Til
author_facet Wyss Richard
Lunt Mark
Brookhart M. Alan
Glynn Robert J.
Stürmer Til
author_sort Wyss Richard
collection DOAJ
description The prognostic score, or disease risk score (DRS), is a summary score that is used to control for confounding in non-experimental studies. While the DRS has been shown to effectively control for measured confounders, unmeasured confounding continues to be a fundamental obstacle in non-experimental research. Both theory and simulations have shown that in the presence of unmeasured confounding, controlling for variables that affect treatment (both instrumental variables and measured confounders) amplifies the bias caused by unmeasured confounders. In this paper, we use causal diagrams and path analysis to review and illustrate the process of bias amplification. We show that traditional estimation strategies for the DRS do not avoid bias amplification when controlling for predictors of treatment. We then discuss estimation strategies for the DRS that can potentially reduce bias amplification that is caused by controlling both instrumental variables and measured confounders. We show that under certain assumptions, estimating the DRS in populations outside the defined study cohort where treatment has not been introduced, or in outside populations with reduced treatment prevalence, can control for the confounding effects of measured confounders while at the same time reduce bias amplification.
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spelling doaj.art-ee68d56c763b42c0971270d357708b412022-12-21T19:22:05ZengDe GruyterJournal of Causal Inference2193-36772193-36852014-09-012213114610.1515/jci-2014-0009Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk ScoreWyss Richard0Lunt Mark1Brookhart M. Alan2Glynn Robert J.3Stürmer Til4Department of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435, USAArthritis Research UK Epidemiology Unit, Centre for Musculoskeletal Research, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UKDepartment of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435, USADepartment of Biostatistics, Harvard School of Public Health, Brigham & Women’s Hospital, Boston, MA, USADepartment of Epidemiology, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7435, USAThe prognostic score, or disease risk score (DRS), is a summary score that is used to control for confounding in non-experimental studies. While the DRS has been shown to effectively control for measured confounders, unmeasured confounding continues to be a fundamental obstacle in non-experimental research. Both theory and simulations have shown that in the presence of unmeasured confounding, controlling for variables that affect treatment (both instrumental variables and measured confounders) amplifies the bias caused by unmeasured confounders. In this paper, we use causal diagrams and path analysis to review and illustrate the process of bias amplification. We show that traditional estimation strategies for the DRS do not avoid bias amplification when controlling for predictors of treatment. We then discuss estimation strategies for the DRS that can potentially reduce bias amplification that is caused by controlling both instrumental variables and measured confounders. We show that under certain assumptions, estimating the DRS in populations outside the defined study cohort where treatment has not been introduced, or in outside populations with reduced treatment prevalence, can control for the confounding effects of measured confounders while at the same time reduce bias amplification.https://doi.org/10.1515/jci-2014-0009bias amplificationprognostic scoreunmeasured confoundingpath analysiscausal diagrams
spellingShingle Wyss Richard
Lunt Mark
Brookhart M. Alan
Glynn Robert J.
Stürmer Til
Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
Journal of Causal Inference
bias amplification
prognostic score
unmeasured confounding
path analysis
causal diagrams
title Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
title_full Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
title_fullStr Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
title_full_unstemmed Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
title_short Reducing Bias Amplification in the Presence of Unmeasured Confounding through Out-of-Sample Estimation Strategies for the Disease Risk Score
title_sort reducing bias amplification in the presence of unmeasured confounding through out of sample estimation strategies for the disease risk score
topic bias amplification
prognostic score
unmeasured confounding
path analysis
causal diagrams
url https://doi.org/10.1515/jci-2014-0009
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