AB0410 DISCONTINUATION OF ORAL GLUCOCORTICOID AFTER INITIATION OF BIOLOGICAL DMARD DUE TO A HIGHER DOSE OF METHOTREXATE; A RETROSPECTIVE OBSERVATIONAL STUDY BASED ON DATA FROM A JAPANESE MULTICENTER REGISTRY STUDY

Abstract

Background In the treatment of rheumatoid arthritis, glucocorticoid that provide anti-inflammatory effects in the early stage of treatment is an important drug. We recommend discontinuing of glucocorticoid as much as possible within 6 months[1], but many patients have taken oral glucocorticoid for the long term in daily clinical practice. The frequency of use of glucocorticoid has gradually declined, and there are several reports on discontinuation of glucocorticoid due to the initiation of bDMARD[2, 3]. However, there is no report showing the relation between discontinuation of glucocorticoid and MTX dose. Objectives The aim of this study is to examine association of methotrexate (MTX) dose with discontinuation of glucocorticoid after one year since initiation of biological DMARD (bDMARD) as 1st bDMARD. Methods We established the large observational cohort, the Nagoya University orthopedic facility multicenter study (TBCR), and a total of 3119 patients used biological DMARD. 564 patients who used glucocorticoid and MTX when bDMARD was initiated as 1st bDMARD were enrolled. In the first study, we examined predictive factors of discontinuation of glucocorticoid after one year since initiation of bDMARD by using multivariate analysis in the two groups, which patients continued to use glucocorticoid and discontinued to use glucocorticoid. In the second study, we adjusted the background at the time of initiation of bDMARD by using propensity score matching (PS) in the two groups, MTX≤8mg (L group) and MTX>8mg (H group). Results 400 patients continued to use glucocorticoid and 164 patients discontinued to use glucocorticoid. In the multivariate analysis, age (Odds ratio (OR)0.98), MTX dose (OR1.09) and glucocorticoid dose (OR0.88) were independently predictive factors of discontinuation of glucocorticoid. When we adjusted age, disease duration, sex, disease activity, RF/ACPA, glucocorticoid dose by using PS matching, 105 pairs were extracted. There were obvious significant differences between 24 patients (22.9%) in the L group and 43 cases (41.0%) in the H group (P = 0.007), where glucocorticoid was discontinued at one year after the initiation of bDMARD. Conclusion This cohort study investigated the association with discontinuation of oral glucocorticoid and MTX dose in the patients treated with bDMARD. TBCR revealed that, in the clinical practice, glucocorticoid use was decreasing in the patients treated with bDMARD. MTX dose at the time of initiation of bDMARD was predictive factor of discontinuation of glucocorticoid. A higher dose of MTX associated with discontinuation of glucocorticoid in the patients treated with bDMARD.