How to study determinants related to medication adherence in newly diagnosed polyarthritis patients for the development of a prediction instrument

Annelieke Pasma,1,2 Johanna MW Hazes,1 Jolanda J Luime,1 Jan JV Busschbach,2 Adriaan van ’t Spijker2 1Department of Rheumatology, Erasmus MC, University Medical Center Rotterdam, 2Department of Psychiatry, Section of Medical Psychology and Psychotherapy, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands Introduction: 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/design: 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. Discussion: 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. Keywords: adherence, chronic disease, methodology, arthritis, medication