Assessment on Treatments With Conventional Synthetic Disease-modifying Drugs Before Initiating Biologics in Patients With Rheumatoid Arthritis in Korea: A Population-based Study

OBJECTIVE: To assess pre-biologic treatments with conventional synthetic disease-modifying drugs (csDMARDs) prior to biologics initiation among patients with rheumatoid arthritis (RA). METHODS: Using Korea National Health Insurance database, we examined pre-biologic treatments of RA patients on the following four items whether 1) initial methotrexate (MTX) therapy was given, 2) MTX dose was escalated up to ≥15 mg/week within 1-year post-diagnosis, 3) prednisone-equivalent glucocorticoid was used at a dose of ≤7.5 mg/day, and 4) glucocorticoid was discontinued within 6 months of treatment. Multivariable logistic regressions identified predictors of items 2) and 4) fulfillment. RESULTS: Among 6,986 biologics initiators with RA, 54.9% used MTX as the 1st csDMARD. Within 1-year post-diagnosis, 85.2% used MTX with half of them achieving a dose of ≥15 mg/week. The majority (75.2%) of patients used glucocorticoids initially and 64.5% were still on glucocorticoids at 6 months, mostly at a dose of ≤7.5 mg/day. csDMARD combination was observed in 85.7%. Item 2) fulfillment was associated with males, younger age, glucocorticoid, combination therapy, cyclo-oxygenase-2 inhibitors, and viral hepatitis. Item 4) fulfillment was associated with males, MTX dose of ≥15 mg/week, combination therapy, viral hepatitis, and hospitalizations. CONCLUSION: RA patients in Korea were predominantly treated with MTX-based csDMARD combination plus glucocorticoids before initiating biologics, without sufficient MTX dose escalation or glucocorticoid discontinuation. Items 2) and 4) fulfillments were associated with patient age and gender, concomitant treatments, and comorbidities.