To study frequency, possible baseline predictors, timing, and duration of sustained remission [SR; defined as 28-joint Disease Activity Score (DAS28) < 2.6 for at least 6 mos] in patients with established rheumatoid arthritis (RA) treated with different tumor necrosis factor (TNF) inhibitors [etanercept (ETN), infliximab (IFX), adalimumab (ADA)]. In addition, the aim was to compare (head-to-head) the effectiveness of individual drugs in patients receiving their first anti-TNF treatment.
All anti-TNF-treated patients with RA included in the observational South Swedish Arthritis Group register were eligible. We identified the patients' first SR periods (time between first visit after treatment initiation with DAS28 < 2.6 and subsequent visit with DAS28 ≥ 2.6). Baseline predictors of SR in biologic-naive patients were studied using multivariate regression models. Remission duration and timing of remission start was estimated with Kaplan-Meier curves.
Of the 2416 patients included, 382 (15.8%) fulfilled the criteria for SR. Median estimated duration of SR was 5.25 years. Predictors for SR were male sex, low Health Assessment Questionnaire, low DAS28, methotrexate (MTX) treatment, and the calendar year of treatment start. OR for achieving SR within the first 12 months of treatment were 1.86 for ETN (95% CI 1.33-2.61) compared to IFX. HR for 4 years of SR were 1.32 for ETN (95% CI 1.01-1.74) and 1.84 for ADA (95% CI 1.23-2.78), with IFX as the reference drug.
SR was uncommon in patients with RA treated with anti-TNF in clinical practice. However, patients remained in SR for a substantial period of time. Concomitant MTX treatment predicts remission. ETN and ADA were more likely in reaching SR.