THU0178 PREDICTORS OF BIOLOGIC DISEASE MODIFYING ANTI-RHEUMATIC DRUG INITIATION AMONG PATIENTS WITH RHEUMATOID ARTHRITIS IN KOREA
Authors: E. H. Park, A. Shin, Y. J. Ha, Y. J. Lee, E. B. Lee, Y. W. Song, E. H. Kang
Journal: Annals of the Rheumatic Diseases (2020)

Background: Biological disease-modifying anti-rheumatic drugs (bDMARDs) have significantly improved clinical prospects for patients with rheumatoid arthritis (RA). Objectives: To identify predictors of bDMARDs initiation in RA patients. Methods: Using 2002-2016 Korea National Health Insurance Service database, we conducted a nested case-control study on RA patients. Four conventional DMARD (cDMARD) users were selected by risk set sampling per each bDMARD user, matched on the calendar year/month of RA diagnosis. Potential predictors were separately assessed for two periods, 1 year after RA diagnosis and 1 year prior to bDMARD initiation, by logistic regression analyses estimating odds ratio (OR) and 95% confidence interval (CI). Results: The study included 27,940 cDMARD users and 6,985 bDMARD users. Younger age, initial use of a less potent cDMARD (sulfasalazine), corticosteroid use, and higher maximal methotrexate (MTX) dose during 1 year post-diagnosis were positive predictors for later bDMARD initiation, while male gender, initial use of a potent cDMARD (MTX, leflunomide, or tacrolimus), initial MTX dose of ≥10mg/wk, and initial cDMARD combination were negative predictors (Table 1). Use of non-MTX DMARDs (leflunomide, sulfasalazine, or tacrolimus), higher # of cDMARD used, subcutaneous administration of MTX, corticosteroid therapy, and higher maximal MTX dose were positive predictors of subsequent bDMARD. Although higher comorbidity score during 1 year before bDMARD initiation was a positive predictor, the effect was heterogenous by involved systems (Table 2). Table 1. Predictors of bDMARD initiation among RA patients during 1-year post-diagnosis Predictors OR (95% CI) P-value Age (/1 year) 0.977 (0.974-0.980) &lt;0.001 Sex (male vs. female) 0.850 (0.787-0.918) &lt;0.001 1st cDMARD at RA diagnosis (yes vs. no) Methotrexate 0.540 (0.476-0.614) &lt;0.001 Leflunomide 0.463 (0.388-0.552) &lt;0.001 Sulfasalazine 1.305 (1.197-1.424) &lt;0.001 Tacrolimus 0.181 (0.083-0.395) &lt;0.001 Initial MTX dose (≥10mg/week vs. &lt;10mg/week) 0.539 (0.506-0.575) &lt;0.001 Initial cDMARD combination (yes vs. no) 0.621 (0.530-0.727) &lt;0.001 Subcutaneous MTX use (yes vs. no) 1.456 (1.156-1.834) 0.001 Maximal MTX dose (/1mg) 1.012 (1.008-1.016) &lt;0.001 Corticosteroids use (yes vs. no) 2.805 (2.345-3.355) &lt;0.001 Table 2. Predictors of bDMARD initiation among RA patients during 1-year prior to bDMARD initiation Predictors OR (95% CI) P-value Age (/1 year) 0.970 (0.967-0.974) &lt;0.001 Non-MTX cDMARD use (yes vs. no) 1 Leflunomide 1.765 (1.573-1.980) &lt;0.001 Sulfasalazine 1.465 (1.297-1.654) &lt;0.001 Tacrolimus 2.070 (1.796-2.387) &lt;0.001 Subcutaneous MTX use (yes vs. no) 1.731 (1.577-1.900) &lt;0.001 Maximal MTX dose (/1mg) 2.568 (1.921-3.433) &lt;0.001 Glucocorticoid use (yes vs. no) 1.015 (1.010-1.021) &lt;0.001 Comorbidity index (/1 point) 1.124 (1.076-1.175) &lt;0.001 Individual comorbidities (yes vs. no) Stroke/ transient ischemic attack 0.764 (0.626-0.932) 0.008 Atrial fibrillation 0.666 (0.455-0.973) 0.036 Diabetes mellitus 1.208 (1.076-1.356) 0.001 Joint replacement therapy 1.788 (1.341-2.384) &lt;0.001 Hepatitis B infection 1.559 (1.238-1.964) &lt;0.001 Hepatitis C infection 2.117 (1.532-2.925) &lt;0.001 Chronic obstructive pulmonary disease 1.118 (1.012-1.234) 0.028 1 MTX was excluded since all bDMARD initiators were required to use MTX before bDMARD initiation. Conclusion: In this population-based nationwide study, we identified period-specific predictors of bDMARD initiation among RA patients in Korea. Overall, initial aggressive RA treatment after RA diagnosis were associated with less use of later bDMARD, while highly intensive therapy observed just before bDMARD initiation reflects refractory nature of RA during this period. Disclosure of Interests: None declared