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

Figures & data

Table 1 Possible determinants of adherence

Note: Underlined text: these factors are taken into account by our study.

Abbreviations: AHI, Arthritis Helplessness Index; BMQ, Beliefs about Medicines Questionnaire; CORS, Coping with Rheumatic Stressors questionnaire; CPAQ, Chronic Pain Acceptance Questionnaire; Anxiety and Depression Scale; IPQ-R, Revised Illness Perception Questionnaire; MHLC, Multidimensional Health Locus of Control Scale; MUSE, Medication Understanding and Use Self-efficacy; NPV-2, Nederlandse persoonlijkheidsvragenlijst; PASS-20, short version Pain Anxiety Symptoms Scale; PCCL, Pijn Coping Cognitie Lijst; TNF-I, tumor necrosis factor inhibitor.

Figure 1 Extended Health Belief Model.

Table 2 Flowchart of measures during follow up

Measure	T0	T1	T2	T3	T4
Adherence
MEMS	Continuous
CQR	X	X	X	X	X
MTX polyglutamates		X	X	X	X
Clinical outcome
DAS28	X	X	X	X	X
HAQ	X	X	X	X	X
Factors associated with adherence
BMQ	X		X
MUSE	X		X
HADS	X		X
Item pool	X		X

Note: X, measured at the time point indicated in the column heading.

Abbreviations: BMQ, Beliefs about Medicines Questionnaire; CQR, Compliance Questionnaire Rheumatology; DAS28, Disease Activity Score 28; HADS, Hospital Anxiety and Depression Scale; HAQ, Health Assessment Questionnaire; MEMS, medication event monitoring systems; MTX, methotrexate; MUSE, Medication Understanding and Use Self-efficacy scale; T0, baseline; T1, 3 months after T0; T2, 6 months after T0; T3, 9 months after T0; T4, 12 months after T0.