PERFORMANCE OF THE PRELIMINARY DEFINITION OF IMPROVEMENT IN JUVENILE CHRONIC ARTHRITIS PATIENTS TREATED WITH METHOTREXATE

Objective-To investigate the performance of the core set of outcome me asures and the preliminary definition of improvement (PDI) in the asse ssment of response to methotrexate (MTX) treatment in children with ju venile chronic arthritis (JCA). Methods-Data were obtained from an ope n label, non-controlled trial designed to investigate the efficacy of MTX in children with. JCA. All patients had the core set of variables assessed at baseline and after six months of treatment. Variables in t he core set are: (1) physician global assessment of disease activity; (2) parent or patient (if appropriate in age) global assessment of ove rall well being; (3) functional ability; (4) number of joints with act ive arthritis; (5) number of joints with Limited range of motion; (6) erythrocyte sedimentation rate. The PDI specifies that to be classifie d as improved, a patient must show at least 30% improvement from basel ine in three of any six variables in the core set, with no more than o ne of the remaining variables worsening by more than 30%. Results-A to tal of ill JCA patients were included in the study. According to the P DI, after six months of MTX treatment 73 patients (66%) were classifie d as improved and 38 (34%) as not improved. Among the core set variabl es, parent assessment detected the highest percentage of patients impr oved (72%) and functional assessment the lowest (37%). Conclusion-The PDI identifies about two thirds of patients with JCA treated with low dose MTX as improved. This proportion is similar to that expected to i mprove based upon a previous controlled study of low dose, oral MTX an d provides preliminary evidence of the definition's validity.