Psychometric properties of three medication adherence scales in patients with rheumatoid arthritis.

Patient adherence to their health care protocols is important to encourage the best health outcomes in rheumatoid arthritis (RA); however, little attention has been given to assessing the psychometric properties of adherence measures in this patient population. The purpose of this study was to evaluate the psychometric properties of three existing self-report measures of medication adherence in a sample of patients with RA--the compliance-questionnaire-rheumatology (CQR), the Medication Adherence Report Scale (MARS), and the medication adherence scale (MAS). A cross-sectional study of 108 clinic patients with rheumatoid arthritis was conducted to evaluate the reliability and validity of the measures.