title: A Bayesian framework to account for uncertainty due to missing binary outcome data in pairwise meta-analysis.
abstract: Missing outcome data are a common threat to the validity of the results from randomised controlled trials (RCTs), which, if not analysed appropriately, can lead to misleading treatment effect estimates. Studies with missing outcome data also threaten the validity of any meta-analysis that includes them. A conceptually simple Bayesian framework is proposed, to account for uncertainty due to missing binary outcome data in meta-analysis. A pattern-mixture model is fitted, which allows the incorporation of prior information on a parameter describing the missingness mechanism. We describe several alternative parameterisations, with the simplest being a prior on the probability of an event in the missing individuals. We describe a series of structural assumptions that can be made concerning the missingness parameters. We use some artificial data scenarios to demonstrate the ability of the model to produce a bias-adjusted estimate of treatment effect that accounts for uncertainty. A meta-analysis of haloperidol versus placebo for schizophrenia is used to illustrate the model. We end with a discussion of elicitation of priors, issues with poor reporting and potential extensions of the framework. Our framework allows one to make the best use of evidence produced from RCTs with missing outcome data in a meta-analysis, accounts for any uncertainty induced by missing data and fits easily into a wider evidence synthesis framework for medical decision making.
authors: School of Social and Community Medicine, University of Bristol, Bristol, U.K.
authors: N L
authors: NL
authors: Turner
authors: S
authors: S
authors: Dias
authors: A E
authors: AE
authors: Ades
authors: N J
authors: NJ
authors: Welton
mesh_terms: D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001499:Bayes Theorem; D015982:Bias; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000706:statistics & numerical data*; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012196:Review Literature as Topic; D012559:Schizophrenia / Q000188:drug therapy; D035501:Uncertainty
chemical_list: D014150:Antipsychotic Agents; D006220:Haloperidol
keywords: Bayesian; bias; decision making; meta-analysis; missing data; pattern-mixture model