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 (
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) | <0.001 |
Sex (male vs. female) | 0.850 | (0.787-0.918) | <0.001 |
1st cDMARD at RA diagnosis (yes vs. no) | |||
Methotrexate | 0.540 | (0.476-0.614) | <0.001 |
Leflunomide | 0.463 | (0.388-0.552) | <0.001 |
Sulfasalazine | 1.305 | (1.197-1.424) | <0.001 |
Tacrolimus | 0.181 | (0.083-0.395) | <0.001 |
Initial MTX dose (≥10mg/week vs. <10mg/week) | 0.539 | (0.506-0.575) | <0.001 |
Initial cDMARD combination (yes vs. no) | 0.621 | (0.530-0.727) | <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) | <0.001 |
Corticosteroids use (yes vs. no) | 2.805 | (2.345-3.355) | <0.001 |
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) | <0.001 |
Non-MTX cDMARD use (yes vs. no) 1 | |||
Leflunomide | 1.765 | (1.573-1.980) | <0.001 |
Sulfasalazine | 1.465 | (1.297-1.654) | <0.001 |
Tacrolimus | 2.070 | (1.796-2.387) | <0.001 |
Subcutaneous MTX use (yes vs. no) | 1.731 | (1.577-1.900) | <0.001 |
Maximal MTX dose (/1mg) | 2.568 | (1.921-3.433) | <0.001 |
Glucocorticoid use (yes vs. no) | 1.015 | (1.010-1.021) | <0.001 |
Comorbidity index (/1 point) | 1.124 | (1.076-1.175) | <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) | <0.001 |
Hepatitis B infection | 1.559 | (1.238-1.964) | <0.001 |
Hepatitis C infection | 2.117 | (1.532-2.925) | <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