Assessment of adherence to disease-modifying anti-rheumatic drugs in rheumatoid arthritis

Objectives This work aimed to assess treatment adherence in rheumatoid arthritis patients with several tools and to identify factors associated with poor adherence. Method Between February and December 2015, 183 patients were included in this cross-sectional study. A homemade 23-item self-questionnaire was filled by patients during an outpatient consultation or a day hospitalization stay. Morisky Medication Adherence Scale (MMAS)-4, MMAS-8 and Girerd scores were extracted from this homemade questionnaire. Medication possession ratio (MPR) was then calculated. For identification of factors associated with nonadherence, patients were divided in two groups according to MMAS-8 results differentiating patients with good or bad adherence to treatments. Results Of the 183 patients, 59% received a combination of biologic and conventional synthetic disease-modifying drugs, 22% a biological treatment alone, and 19% a conventional DMARD alone. Respectively, 3%, 10%, and 7% were considered as low adherent according to MMAS-4, MMAS-8, and Girerd scores. MPR was calculated for 84/183 patients; 23% were low adherent. The need for a help in preparing the drugs ( p = 0.05; OR = 6.12; 95% CI: 0.86 to 268.90) and concomitant diabetes ( p < 0.001; OR = 0.045, 95% CI: 0.001 to 0.299) was higher in patients with good adherence. Presence of a patient’s relative reminding to take medications was associated with low adherence (p = 0.002; OR = 4.32, 95% CI: 1.41 to 13.11). Conclusions This study highlighted the difficulty of assessing treatment adherence in rheumatoid arthritis patients despite four different tools. Objective measures by MPR indicated a higher proportion of poor adherent patients than self-questionnaires. Key Points • Proportion of patients considered as low adherent ranged from 3 to 27% according to the method of evaluation . • The use of a pillbox and/or the preparation of drugs by a patient’s relative was associated with good adherence . • The presence of a patient’s relative reminding to take medication was associated with low adherence .