Translation and Validation of the Urdu Version of the Methotrexate Intolerance Severity Score in Patients with Inflammatory Arthritis

Abstract

Abstract Background: Methotrexate (MTX) is a cornerstone in the treatment of patients with inflammatory arthritis but is not tolerated well by patients. This intolerance can be identified using the Methotrexate Intolerance Severity Score (MISS). Objective: The objective of this study was to translate and validate the MISS in the Urdu language. Materials and Methods: It was a cross-sectional study done at the Department of Rheumatology, Combined Military Hospital, Lahore, from December 1, 2021, to March 31, 2022. A total of 181 patients with inflammatory arthritis taking MTX for >3 months participated in the study. The translated Urdu version was tested in these patients who attempted the questionnaire twice with a gap of 2 weeks. Cronbach’s alpha, item correlations, and kappa coefficients were used to evaluate internal consistency, acceptability, and reproducibility. A culturally admissible Urdu version of MISS was developed. Results: The results show a 90% response rate, <1% missing data with very good acceptability, and understanding of patients. There were satisfactory inter-item, dimension-item, and inter-dimension correlations. The kappa coefficient was more than 0.90 for most items except associative stomachache (0.79). Cronbach’s alpha coefficient was 0.78, much higher than 0.6, and in the validation cohort, it was 0.74. The internal and external consistency results for validation were satisfactory. There was a good understanding between the test and retest for every patient. The MISS showed a sensitivity of 72% and a specificity of 100% at a discriminative cutoff value of 6.5. Of the 181 patients receiving MTX, 48 (26.5%) experienced MTX intolerance. Conclusion: This validated Urdu version MISS is a sensitive and specific tool that can better detect this MTX intolerance. It discriminates well between MTX-tolerant and intolerant patients.