title: Model assessment in dynamic treatment regimen estimation via double robustness.
abstract: Dynamic treatment regimens (DTRs) recommend treatments based on evolving subject-level data. The optimal DTR is that which maximizes expected patient outcome and as such its identification is of primary interest in the personalized medicine setting. When analyzing data from observational studies using semi-parametric approaches, there are two primary components which can be modeled: the expected level of treatment and the expected outcome for a patient given their other covariates. In an effort to offer greater flexibility, the so-called doubly robust methods have been developed which offer consistent parameter estimators as long as at least one of these two models is correctly specified. However, in practice it can be difficult to be confident if this is the case. Using G-estimation as our example method, we demonstrate how the property of double robustness itself can be used to provide evidence that a specified model is or is not correct. This approach is illustrated through simulation studies as well as data from the Multicenter AIDS Cohort Study.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1020 Pine Avenue West, Montreal, QC H3A 1A2, Canada. michael.wallace@mcgill.ca.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Wallace
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1020 Pine Avenue West, Montreal, QC H3A 1A2, Canada.
authors.forename: Erica E M
authors.initials: EE
authors.lastname: Moodie
authors.affiliation: Department of Mathematics and Statistics, McGill University, Montreal, QC H3A 2K6, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Stephens
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy; D018791:CD4 Lymphocyte Count; D003198:Computer Simulation; D006801:Humans; D008297:Male; D015233:Models, Statistical; D064887:Observational Studies as Topic / Q000706:statistics & numerical data; D057285:Precision Medicine / Q000706:statistics & numerical data*; D013812:Therapeutics / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D015215:Zidovudine / Q000008:administration & dosage
chemical_list: D015215:Zidovudine
keywords: Adaptive treatment strategies; Double robustness; Dynamic treatment regimens; G-estimation; Model selection; Personalized medicine