title: How to study determinants related to medication adherence in newly diagnosed polyarthritis patients for the development of a prediction instrument.
abstract: BACKGROUND
  For patients with a chronic disease, the appropriate use of medication is the key to manage their illness. Adherence to medication is therefore important. Adherence can be divided into three parts: the initiation part, the execution phase, and the discontinuation part. Little is known about the determinants of the initiation part. For this reason, we describe the conduct of a stepwise procedure to study determinants of medication initiation for patients with a chronic disease.
  
  
  METHODS
  The stepwise procedure comprises of eliciting a list of all potential determinants via literature review, interviewing patients, and consulting an expert panel. This is followed by embedding the determinants in a theoretical framework, developing a questionnaire, and choosing adherence measurement methods. The consecutive steps that we conducted for the development of a tool for the prediction of adherence in our study sample of early arthritis patients are described.
  
  
  CONCLUSIONS
  Although we used a thorough procedure, there are still some pitfalls to take into account, such as the choice of theoretical framework. A strength of this study is that we use multiple adherence measurement methods and that we also take clinical outcomes into account.
authors.affiliation: Department of Rheumatology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands ; Department of Psychiatry, Section of Medical Psychology and Psychotherapy, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: Annelieke
authors.initials: A
authors.lastname: Pasma
authors.affiliation: Department of Rheumatology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: Johanna Mw
authors.initials: JM
authors.lastname: Hazes
authors.affiliation: Department of Rheumatology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: Jolanda J
authors.initials: JJ
authors.lastname: Luime
authors.affiliation: Department of Psychiatry, Section of Medical Psychology and Psychotherapy, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: Jan Jv
authors.initials: JJ
authors.lastname: Busschbach
authors.affiliation: Department of Psychiatry, Section of Medical Psychology and Psychotherapy, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
authors.forename: Adriaan
authors.initials: A
authors.lastname: van 't Spijker
keywords: adherence; arthritis; chronic disease; medication; methodology