Performance of the preliminary definition of improvement in juvenile idiopathic arthritis patients treated with methotrexate: experience from Bangladesh

Objective: To evaluate the performance of Preliminary Definition of Improvement (PDI) in juvenile idiopathic arthritis (JIA) patients treated with methotrexate (MTX). Methods: This was a prospective observational study done in the paediatric department of Bangabandhu Sheikh Mujib Medical University (BSMMU) during April 2005-August 2006. All the patients fulfilling the International League of Associations for Rheumatology classification criteria had the American College of Rheumatology core set of variables assessed at baseline and follow-up at the 4th, 12th and 24th week of treatment. Variables in the core set are: (1) physician's global assessment of disease activity; (2) parents' or patients' global assessment of disease activity; (3) functional ability; (4) number of joints with active arthritis; (5) number of joints with limited range of motion; and (6) erythrocyte sedimentation rate. Patients were classified as improved or not improved according to PDI. The following definition of improvement was selected: 30% improvement from baseline in three of any six variables in the core set with no more than one of the remaining variables worsening by > 30%. Results: A total of 40 children with JIA, completed 6 months treatment. At the end of 6 months, most of the patients (92.5%) had been declared as improved according to PDI. Among the core set variables, active arthritis, physicians' and patients' global assessment of disease activity, detected the highest percentage of patients improved (92.5%) and functional assessment detected the lowest (37%). Conclusion: The PDI identified that a maximum number of JIA patients treated with MTX had improved.