AB0181 COULD TITERS OF ACPA PREDICT THE SEVERITY OF RHEUMATOID ARTHRITIS, ANALYSIS OF DATA DURING A 3-YEARS FOLLOW-UP?
Authors: R. Shpatz, Y. Braun-Moscovici, A. Balbir-Gurman
Journal: Annals of the Rheumatic Diseases (2020)

Background: Rheumatoid Factor (RF) and/or Anti Citrullinated Protein Antibodies (ACPA). Are included in classification criteria of Rheumatoid arthritis (RA); their presence correlates with RA severity. The influence of ACPA titer on RA course and outcome in long-term follow-up is limited. Objectives: To check the correlation between ACPA titers at the time of RA diagnosis to RA features and severity during 3 years follow-up. Methods: We performed a retrospective study on patients treated at our institution during the years 2006-2015 with known ACPA titers at RA diagnosis, who completed at least 3 years of follow-up. Patients (pts) were divided according to ACPA titer: A - seronegative (&lt;15 U/ml), B - weak positive (15-49 U/ml) and C - strong positive (&gt;50 U/ml) with subdivision to C-1 - moderately high (50-99 U/ml), C-2 - high (100-299 U/ml) and C-3 - very high (&gt;300 U/ml). Patient’s data including DAS28, bone erosion on hands and/or foot X-rays, treatments with corticosteroids and DMARDs and hospitalizations due to flares. Chi-Square and Mann-Whitney method were used for statistical analysis; p&lt;0.05 was considered statistically significant. Results: Among 850 pts with RA, 133 (mean age 55 years, 65% female) met the inclusion criteria: group A: 55 (42%) pts, group B: 18 (13%) pts, group C: 60 (45%) pts [C1- 10 pts, C2-21 pts and C3-29 pts]. Most of the characteristics were similar between the groups (including C subgroups). There were no significant differences between the groups in terms of tender and/or swollen joints, acute phase reactants, bone erosions, need for corticosteroids or DMARDs, hospitalizations, number of DMARDs and number of biologicals. There was significant correlation between ACPA titers and positive RF (p&lt;0.0001); it was consistent in all patients groups. Higher ACPA titers were associated with greater percentage of patients with positive RF. The percentage of male was higher in subgroup with highest ACPA: 25% in ACPA-negative group compared to 45% in the strong positive group (group C-3); it correlated with current or ever smoking. DAS28 was high in all groups without significant difference; over 80% of patients had DAS28 higher than 3.2 and 50-60% had a value higher than 5.2. During the 3-year follow-up, 95% of pts received prednisone with an average daily dose of 14.8 mg (SD, 8.9 mg), 50% of pts received more than 15 mg prednisone daily. The average number of synthetic and biological DMARDs was 2.5 (SD 0.73) and 0.56 (SD 0.84) per patient; methotrexate was prescribed in 89% of cases. There were no correlations between negative (group A) or positive ACPA (group B and C) and the variables defined as representing the severity of RA: the percentage of pts with DAS28&gt;3.2 (p=0.136) and DAS28&gt;5.2 (p=0.774). The percentage of pts receiving prednisone dosage higher than 15 mg/day (p=0.828) or at least two synthetic (p=0.846) or biological DMARDs (p=0.668) or their combination (p=0.770) were not significantly different. There was no correlation between ACPA titer and bone erosions (87 pts, p=0.883) during 3 years of follow-up. Finally, there was no correlation between ACPA titers and the number of hospital admissions (p=0.951). Conclusion: In our cohort of RA pts, higher ACPA titers were observed in males with smoking history. Higher ANCA titers correlated with RF positivity but were not identified as predictive factor for RA severity. Disclosure of Interests: Rotem Shpatz: None declared, Yolanda Braun-Moscovici: None declared, Alexandra Balbir-Gurman Consultant of: Novartis