A survey on the medication adherence to methotrexate among rheumatoid arthritis patients treated with self-administered biologic drugs

Methotrexate (MTX) is the most widely used co-therapy among rheumatoid arthritis (RA) patients using biological disease-modifying anti-rheumatic drugs (bDMARDs). However, adherence to MTX treatment remains a concern with estimates of adherence ranging from 59 to 63%. The objective of this study was to assess the self-reported use and adherence to MTX among RA patients treated with self-administered bDMARDs. An electronic questionnaire survey was conducted in 68 community pharmacies in Finland. To be included in the present study patients had to be at least 18 years old, be currently using a self-administered bDMARD and be diagnosed with RA. The results are presented as medians with their respective interquartile ranges (IQR) or percentages. Of the 158 pharmacy customers asked to participate, 135 (85%) consented to complete the questionnaire. The included respondents were predominantly female (72%) with a median age of 55 (IQR 44-65) and rheumatic activity of 3 out of 10 (IQR 2-6.5). The majority (91%) of the included respondents were using TNF-inhibitors and 27% of all patients were on biologic monotherapy. MTX was currently used by 45% of the respondents while 50% were past users. Of the current MTX users, 6.8% identified themselves moderately non-adherent to the treatment. MTX-related adverse events were important factors associated with nonadherence and discontinuation of the treatment. Only 45% of the respondents were currently using MTX co-therapy, but the ones who did were adherent to their treatment. Self-reported adherence may however be subject to social desirability bias and recall bias.