Abstract
The objective of the study was to examine whether disease duration independently predicts treatment response among biologic-naïve patients with rheumatoid arthritis (RA) initiating abatacept in clinical practice. Using the Corrona RA registry (February 2006-January 2015), biologic-naïve patients with RA initiating abatacept with 12-month (±3 months) follow-up and assessment of disease activity (Clinical Disease Activity Index [CDAI]) at initiation and at 12 months were identified. The primary outcome was mean change in CDAI (ΔCDAI) from baseline to 12 months. Secondary outcomes at 12 months included achievement of low disease activity (LDA; CDAI ≤10 in patients with moderate/high disease activity at initiation) and remission (CDAI ≤2.8 in patients with low, moderate or high disease activity at initiation). Linear and logistic regression analyses were performed to examine the relationship between disease duration and response to abatacept. There were 281 biologic-naïve patients with RA initiating abatacept (disease duration 0-2 years, n = 107; 3-5 years, n = 45; 6-10 years, n = 50; >10 years, n = 79). Increased disease duration was associated with older age (p = 0.047), and the median number of prior conventional disease-modifying antirheumatic drugs used was lowest in the 0- to 2-year duration group (p < 0.001). Mean ΔCDAI (SE) ranged from -10.22 (1.19) for 0-2 years to -4.63 (1.38) for >10 years. In adjusted analyses, shorter disease duration was significantly associated with greater mean ΔCDAI (p = 0.015) and greater likelihood of achieving LDA (p = 0.048). In biologic-naïve patients with RA initiating abatacept, earlier disease (shorter disease duration) was associated with greater ΔCDAI and likelihood of achieving LDA.