title: Hierarchical priors for bias parameters in Bayesian sensitivity analysis for unmeasured confounding.
abstract: Recent years have witnessed new innovation in Bayesian techniques to adjust for unmeasured confounding. A challenge with existing methods is that the user is often required to elicit prior distributions for high-dimensional parameters that model competing bias scenarios. This can render the methods unwieldy. In this paper, we propose a novel methodology to adjust for unmeasured confounding that derives default priors for bias parameters for observational studies with binary covariates. The confounding effects of measured and unmeasured variables are treated as exchangeable within a Bayesian framework. We model the joint distribution of covariates by using a log-linear model with pairwise interaction terms. Hierarchical priors constrain the magnitude and direction of bias parameters. An appealing property of the method is that the conditional distribution of the unmeasured confounder follows a logistic model, giving a simple equivalence with previously proposed methods. We apply the method in a data example from pharmacoepidemiology and explore the impact of different priors for bias parameters on the analysis results.
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada. mccandless@sfu.ca
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: McCandless
authors.forename: Paul
authors.initials: P
authors.lastname: Gustafson
authors.forename: Adrian R
authors.initials: AR
authors.lastname: Levy
authors.forename: Sylvia
authors.initials: S
authors.lastname: Richardson
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001499:Bayes Theorem; D015982:Bias; D002316:Cardiotonic Agents / Q000627:therapeutic use; D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D004077:Digoxin / Q000627:therapeutic use; D004232:Diuretics / Q000627:therapeutic use; D005260:Female; D006333:Heart Failure / Q000188:drug therapy / Q000401:mortality; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D008297:Male; D017891:Pharmacoepidemiology / Q000706:statistics & numerical data; D012044:Regression Analysis
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D002316:Cardiotonic Agents; D004232:Diuretics; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D004077:Digoxin