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Intermittent observation of time‐dependent explanatory variables: a multistate modelling approach
Author(s) -
Tom Brian D.M.,
Farewell Ver T.
Publication year - 2011
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4429
Subject(s) - psoriatic arthritis , econometrics , variable (mathematics) , representation (politics) , computer science , ordinal data , set (abstract data type) , outcome (game theory) , variables , arthritis , ordinal scale , statistics , medicine , mathematics , machine learning , mathematical economics , mathematical analysis , politics , political science , law , programming language
Motivated by investigations of factors related to various patient‐reported outcome measures in psoriatic arthritis patients, after controlling for the effect of disease activity on these outcomes, we outline an approach for dealing with a rapidly fluctuating explanatory variable in a multistate model. On the basis of a representation of this variable as an ordinal classification, we suggest the use of an expanded multistate model. We examine the bias in estimating effects associated with other variables via simulation for different modelling choices. We present an analysis of a motivating data set on physical functional disability in psoriatic arthritis patients. Copyright © 2011 John Wiley & Sons, Ltd.