SAT0073 Acpa and rf as predictors of sustained clinical remission in rheumatoid arthritis patients: results from the ontario best practices research initiative (OBRI)
Authors: J.E. Pope, M. Movahedi, E. Rampakakis, A. Cesta, J.S. Sampalis, C. Bombardier
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Positive anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF) are included among the 2010 ACR/EULAR classification criteria for rheumatoid arthritis (RA). Previous studies have shown that autoantibodies are positive predictors of response in RA patients treated with some biologics whereas other studies suggest worse prognosis if positive for ACPA and RF. <h3>Objectives</h3> The purpose of this study was to evaluate the interaction of RF and ACPA in predicting sustained clinical response in a large observational registry of RA patients followed in routine practice. <h3>Methods</h3> RA patients enrolled in the Ontario Best Practices Research Initiative (OBRI) registry, with active disease (≥1 swollen joint), available autoantibody information, and at least 1 follow-up assessment were included in the analysis. Sustained clinical remission was defined as CDAI ≤2.8 in at least 2 sequential visits separated by at least 3 and maximum of 12 months. Time to sustained remission was assessed by plotting cumulative incidence curves and multivariate cox regression. <h3>Results</h3> A total of 970 (30%) out of 3251 patients in the registry were included, of whom 262 (27%) were anti-CCP<sup>neg</sup>/RF<sup>neg</sup>, 60 (6.2%) anti-CCP<sup>pos</sup>/RF<sup>neg</sup>, 117 (12.1%) anti-CCP<sup>neg</sup>/RF<sup>pos</sup>, and 531 (54.7%) anti-CCP<sup>pos</sup>/RF<sup>pos</sup>. At baseline, significant differences were observed between groups in age (p=0.02), CDAI (p=0.03), tender joint count (p=0.02), and HAQ-DI (p=0.002), with anti-CCP<sup>pos</sup>/RF<sup>pos</sup> and anti-CCP<sup>pos</sup>/RF<sup>neg</sup>patients being youngest and having the lowest disease activity and disability. No differences were observed in terms of biologic use (20.2% of patients). Sustained remission was 10% more likely if anti-CCP<sup>pos</sup>, and was achieved by 43.5% of anti-CCP<sup>pos</sup>/RF<sup>pos</sup>patients, 43.3% of anti-CCP<sup>pos</sup>/RF<sup>neg</sup>patients, 31.6% of anti-CCP<sup>neg</sup>/RF<sup>pos</sup>patients and 32.4% of anti-CCP<sup>neg</sup>/RF<sup>neg</sup>patients (p=0.01). Significant differences were observed in the time to achieving sustained clinical response from enrolment in the OBRI based on anti-CCP status (p&lt;0.001), RF status (p=0.06), and both (p=0.004) (figure 1). ACPA<sup>pos</sup>/RF<sup>pos</sup> (median: 3.7 years; 95% CI: 3.0–4.3) and ACPA<sup>pos</sup>/RF<sup>neg</sup> (median: 3.4 years; 95% CI: 2.4-NE) patients achieved sustained remission earlier than ACPA<sup>neg</sup>/RF<sup>neg</sup>patients (median: 5.1 years; 95% CI: 3.7–6.2), respectively (figure 1). Multivariate cox regression adjusting for baseline CDAI score, age and sex also showed differences between groups; statistically significance in anti-CCP<sup>pos</sup>/RF<sup>pos</sup> vs. anti-CCP<sup>neg</sup>/RF<sup>neg</sup>patients (HR [95% CI]: 1.30 [1.01–1.67]; p=0.04). <h3>Conclusions</h3> These results suggest that anti-CCP but not RF positivity may be associated with a higher chance of remission, possibly due to an improved treatment response. <h3>Disclosure of Interest</h3> J. Pope Grant/research support from: OBRI was funded by peer reviewed grants from CIHR (Canadian Institute for Health Research), Ontario Ministry of Health and Long-Term Care (MOHLTC), Canadian Arthritis Network (CAN) and unrestricted grants from: Abbvie, Amgen, Celgene, Hospira, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, Sanofi, and UCB, M. Movahedi Employee of: OBRI, E. Rampakakis Employee of: JSS Medical Research, A. Cesta Employee of: OBRI, J. Sampalis: None declared, C. Bombardier Grant/research support from: OBRI was funded by peer reviewed grants from CIHR (Canadian Institute for Health Research), Ontario Ministry of Health and Long-Term Care (MOHLTC), Canadian Arthritis Network (CAN) and unrestricted grants from: Abbvie, Amgen, Celgene, Hospira, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, Sanofi, and UCB, Consultant for: Dr. Bombardier holds a Canada Research Chair in Knowledge Transfer for Musculoskeletal Care and a Pfizer Research Chair in Rheumatology