title: Adaptive sampling in two-phase designs: a biomarker study for progression in arthritis.
abstract: Response-dependent two-phase designs are used increasingly often in epidemiological studies to ensure sampling strategies offer good statistical efficiency while working within resource constraints. Optimal response-dependent two-phase designs are difficult to implement, however, as they require specification of unknown parameters. We propose adaptive two-phase designs that exploit information from an internal pilot study to approximate the optimal sampling scheme for an analysis based on mean score estimating equations. The frequency properties of estimators arising from this design are assessed through simulation, and they are shown to be similar to those from optimal designs. The design procedure is then illustrated through application to a motivating biomarker study in an ongoing rheumatology research program.
authors.affiliation: Queen's University, 99 University Avenue, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Michael A
authors.initials: MA
authors.lastname: McIsaac
authors.affiliation: University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
mesh_terms: D001168:Arthritis; D015535:Arthritis, Psoriatic / Q000097:blood / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001699:Biometry; D003198:Computer Simulation; D018450:Disease Progression; D004812:Epidemiologic Methods; D015340:Epidemiologic Research Design; D006801:Humans; D019278:Matrix Metalloproteinase 3 / Q000097:blood; D009864:Ontario; D018579:Patient Selection; D010865:Pilot Projects; D012042:Registries; D012219:Rheumatology; D018401:Sample Size; D012494:Sampling Studies; D014495:Universities
chemical_list: D015415:Biomarkers; D019278:Matrix Metalloproteinase 3
keywords: adaptive design; asymptotic efficiency; incomplete data; mean score analysis; response-dependent sampling