Clinical characteristics and variants that predict prognosis of difficult-to-treat rheumatoid arthritis.

Factors influencing prognosis after administration of the last biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) to patients with difficult-to-treat rheumatoid arthritis (D2T_RA) were evaluated in a clinical setting. RA patients who met the EULAR definition of D2T_RA were recruited. These patients were grouped according to success/failure. Success was defined as sustained within light disease activity or discontinued after clinical remission, and all of the following were met, including glucocorticoid (GCS) < 7.5 mg/day, no rapid radiographic progression, and improved quality of life from the beginning of the b/tsDMARD (baseline). Failure was defined as any other condition from success. The primary endpoint of the study was success or failure at 12 months after baseline. Factors influencing success/failure were statistically evaluated. A total of 71 D2T_RA patients were selected, 22 were in the success group and 49 in the failure group. For patients taking GCS and methotrexate (MTX) ≤ 8.6 mg/week, only one was included in the success group and the other 24 were included in the failure group (p < 0.001). Of the 18 patients without GCS and with MTX ≥ 8.7 mg, 12 patients whose 28-joint disease activity score ≤ 1.90 at 3 months or ≤ 2.54 at 6 months were in the success group (p < 0.01). D2T_RA patients with GCS or MTX ≤ 8.6 mg at baseline are considered to be at high risk of repeat D2T_RA. Patients with no GCS and MTX ≥ 8.7 mg are more likely to withdraw from D2T_RA if their disease activity is tightly controlled.