LAUSR

Background Methotrexate (MTX) is the first-choice disease-modifying anti-rheumatic drug (DMARD) for the treatment of juvenile idiopathic arthritis (JIA). During therapy, there are frequent reports of discontinuation of MTX, either by physicians or patient’s own conduct. Through the MTX Intolerance Severity Score questionnaire (MISS), we determined the prevalence of MTX intolerance. Objectives Translate and validate the MTX Intolerance Severity Score questionnaire (MISS) to Portuguese. Methods The MISS was translated into Portuguese following the “Guidelines for the process of cross-cultural adaptation of self-report measures”. The MISS consists of 4 domains: stomachache, nausea, vomiting, and behavioral complaints. Each domain includes three to four items, and for every item, four answers are possible: no complaints (0), mild complaints (1 point), moderate complaints (2 points), and severe complaints (3 points). The points are summed to give a total score from 0 to 36. Statically analysis was performed on the SPSS®, version 21. The psychometric properties were analyzed according to the Consensus based Standards for the Selection of Health Measurement Instruments (COSMIN), analyzing acceptability for each item; internal consistency using Cronbach’s alpha coefficient and reproducibility assessed by Kappa. We plot the ROC curve to evaluate the discriminant validity of the MISS compared to gold standard (clinical interview) and cut-off score was determined. Results We included 220 subjects, 144 patients with JIA in use for least 3 months of MTX and 76 parents. The median age of patients were 18.3 SD±8.7 years. Seventy-three (73%) patients were females and the JIA subtype most frequently observed was polyarticular. Routes of administration of MTX were subcutaneous (81%) and oral (19%). All the subjects answered the MISS with less than 5 minutes. The internal consistency of MISS had a Cronbach’s alpha = 0.851 (patients) and 0.805 (parents), considered good (≥0.8). The reproducibility between the test (40 patients) and the retest done after 15 days (36 patients) was almost perfect (kappa> 0.8). Reliability between patients and parents was almost perfect (kappa> 0.8), except stomachache (anticipatory with kappa = 0.30); considered weak (κ = 0.2 - 0.4) and stomachache by association (κ = 0.54); considered moderate (κ = 0.4 - 0.6). A cut-off scores of 3 showed the best sensitivity (93%) and specificity (71%). Using this cut-off we observed 78 (54.2%) patients intolerant Conclusion MISS is a good tool for physicians, because it can not only measure the intolerance, but also explore the different forms in which it manifests. Although MTX has a great therapeutic index, the adverse reactions are still seen as a major form of abandonment of this pharmacological treatment. Therefore a careful history is essential to identify side effects and adequate treatment to increase adherence. References [1] Bulatovic M, et al. Arthritis&Rheumatism. 2011; 63: 2007-2013. [2] Chausset A, et al. Clin Rheumatol. 2017; 36:1281-1288. [3] Beaton D, et al. Spine.2000; 24:3186-3191. [4] Terwee C, et al. J Clin Epidemiol.2007; 60:34-42. Disclosure of Interests None declared