title: Nested case-control studies: should one break the matching?
abstract: In a nested case-control study, controls are selected for each case from the individuals who are at risk at the time at which the case occurs. We say that the controls are matched on study time. To adjust for possible confounding, it is common to match on other variables as well. The standard analysis of nested case-control data is based on a partial likelihood which compares the covariates of each case to those of its matched controls. It has been suggested that one may break the matching of nested case-control data and analyse them as case-cohort data using an inverse probability weighted (IPW) pseudo likelihood. Further, when some covariates are available for all individuals in the cohort, multiple imputation (MI) makes it possible to use all available data in the cohort. In the paper we review the standard method and the IPW and MI approaches, and compare their performance using simulations that cover a range of scenarios, including one and two endpoints.
authors.affiliation: Department of Mathematics, University of Oslo, P.O.Box 1053, Blindern, 0316, Oslo, Norway. borgan@math.uio.no.
authors.forename: Ørnulf
authors.initials: Ø
authors.lastname: Borgan
authors.affiliation: Department of Medical Statistics, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. Ruth.Keogh@lshtm.ac.uk.
authors.forename: Ruth
authors.initials: R
authors.lastname: Keogh
mesh_terms: D056808:Biostatistics; D016022:Case-Control Studies; D015331:Cohort Studies; D003198:Computer Simulation; D006801:Humans; D016013:Likelihood Functions; D011336:Probability; D016016:Proportional Hazards Models; D016019:Survival Analysis
keywords: Case–cohort; Competing risks; Cox regression; Inverse probability weighting; Matching; Multiple imputation; Nested case–control