Validation of Methotrexate Intolerance Severity Score (MISS) questionnaire to measure methotrexate intolerance among rheumatoid arthritis Egyptian patients

Rheumatoid arthritis (RA) is a systemic autoimmune chronic inflammatory disease, causing progressive disability. Methotrexate (MTX) is the gold standard drug treatment for RA. Long-term use of MTX is associated with intolerance including gastrointestinal effects. In addition, anticipatory, associative, and behavioral symptoms such as anxiety and irritability are also observed which are often inadequately managed, leading to discontinuation of treatment. Methotrexate Intolerance Severity Score (MISS) questionnaire designed to measure MTX intolerance. The work aims to validate the MISS questionnaire Arabic version for the detection of MTX intolerance among Egyptian RA patients to halt the progression of the disease.

A total of 80 patients were involved in this study. Of those, 67 (83.8%) were females with a mean disease duration of 6.9 ± 6.1 years. Forty-eight patients (60%) were intolerant to MTX and 32 patients (40%) were tolerant. Comparison between the tolerant group (n = 32) to MTX and the intolerant group (n = 48) revealed a statistically significant difference between them regarding the DAS28 score and HAQ score. Behavioral intolerance is the predominant factor that directs MTX intolerance.

The MISS questionnaire has a good predictive ability to detect MTX intolerance among Egyptian RA patients. Due to its good reliability, serves as an invaluable tool as it detects anticipatory and associative symptoms.