ACPA Antibodies Titer at the Time of Rheumatoid Arthritis Diagnosis Is Not Associated with Disease Severity

Background: Rheumatoid arthritis is a chronic inflammatory and destructive joint disease with the presence of autoantibodies, rheumatoid factor (RF), and anti-citrullinated protein antibodies (ACPA). The presence of RF or ACPA predicts RA severity. Data an the influence of ACPA titer on RA course are limited. Objectives: To determine the correlation between ACPA titers at the time of RA diagnosis to RA features and severity during 3 years of follow-up. Methods: We performed a retrospective study of RA patients treated at our institution during the years 2006-2015 with own ACPA titers at RA diagnosis who completed at least 3 years of follow-up. Patients (N=133) were divided according :to ACPA titer: seronegative (< 15 U/ml, n=55), weakly positive (15-49 LI/rnl, n=18), moderately positive (50-300 U/ml, n=29), and strongly positive (> 300 U/rml, n=31). Patient data, including disease activity score (DAS28), bone erosion on hand and/or foot X-rays, treatments with corticosteroids and disease-modifying-anti-rheumatic drugs (DMARDs), and hospitalizations, were recorded. Chi-square and Mann-Whitney method were used for statistical analysis. P < 0.05 was considered as statistically significant. Results: Male gender, smoking, and RF positivity correlated with ACPA positivity and higher ACPA titers. There was no correlation between ACPA titer and the variables defined as presenting RA severity: higher DAS28, bone erosions, hospitalizations, need far corticosteroids, and conventional and biological DMARDs. Conclusions: Titer of ACPA was not identified as a predictive factor for RA severity.