title: Computationally simple analysis of matched, outcome-based studies of ordinal disease states.
abstract: Outcome-based sampling is an efficient study design for rare conditions, such as glioblastoma. It is often used in conjunction with matching, for increased efficiency and to potentially avoid bias due to confounding. A study was conducted at the Massachusetts General Hospital that involved retrospective sampling of glioblastoma patients with respect to multiple-ordered disease states, as defined by three categories of overall survival time. To analyze such studies, we posit an adjacent categories logit model and exploit its allowance for prospective analysis of a retrospectively sampled study and its advantageous removal of set and level specific nuisance parameters through conditioning on sufficient statistics. This framework allows for any sampling design and is not limited to one level of disease within each set, such as in previous publications. We describe how this ordinal conditional model can be fit using standard conditional logistic regression procedures. We consider an alternative pseudo-likelihood approach that potentially offers robustness under partial model misspecification at the expense of slight loss of efficiency under correct model specification for small sample sizes. We apply our methods to the Massachusetts General Hospital glioblastoma study.
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, MA, U.S.A.|Biostatistics Center, Massachusetts General Hospital, Boston, MA, U.S.A.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Betensky
authors.affiliation: Biostatistics Center, Massachusetts General Hospital, Boston, MA, U.S.A.
authors.forename: Jackie
authors.initials: J
authors.lastname: Szymonifka
authors.affiliation: Center for Neuro-Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, U.S.A.
authors.forename: Eudocia Q
authors.initials: EQ
authors.lastname: Lee
authors.affiliation: Pathology Service, Massachusetts General Hospital, Boston, MA, U.S.A.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Nutt
authors.affiliation: Brain Tumor Center, Massachusetts General Hospital, Boston, MA, U.S.A.
authors.forename: Tracy T
authors.initials: TT
authors.lastname: Batchelor
mesh_terms: D056808:Biostatistics / Q000379:methods*; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D003198:Computer Simulation; D005909:Glioblastoma / Q000401:mortality / Q000473:pathology; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: adjacent categories model; conditional logistic regression; glioblastoma; outcome-based sampling; pseudo-likelihood