SAT0032 INCIDENCE OF RHEUMATOID ARTHRITIS IN PATIENTS WITH NEW ONSET OF MUSCULOSKELETAL SYMPTOMS AND ANTI-CPP POSITIVITY COMPARED TO ANTI-CPP NEGATIVE PATIENTS
Authors: S. Dauth, M. Köhm, T. Oberwahrenbrock, U. Henkemeier, T. Rossmanith, K. Mergenthal, J. J. Petersen, H. Burkhardt, F. Behrens
Journal: Annals of the Rheumatic Diseases (2020)

Background: Rheumatoid Arthritis (RA) is a chronic inflammatory joint disease. Strategies for its early detection and diagnosis are of high importance as prompt treatment improves clinical and structural outcome. Autoantibodies against cyclic citrullinated proteins (anti-CCP) have been associated with RA-development. Non-specific musculoskeletal (nsMSK) symptoms are often described prior to RA development. Majority of patients with nsMSK symptoms present to their general practice (GP) first. Studies of early arthritis cohorts have shown that many early arthritis patients cannot be accurately diagnosed at their first visit and are often referred as undifferentiated arthritis patients. Objectives: To evaluate the incidence of anti-CCP positivity in patients with new onset of nsMSK symptoms and the incidence of RA in these patients over a 3-year follow-up period compared to anti-CPP negative patients. Methods: In this prospective study (PANORA), 978 patients with new onset of nsMSK symptoms were included in 77 GP sites in Germany. Patients with a positive anti-CCP rapid-test (CCPoint®) were referred to Rheumatology Department (RD) for rheumatological assessment, RA-evaluation and an anti-CCP validation test (ELISA). ELISA anti-CCP positive patients without RA were monitored every 6 months for a total follow-up of 36 months or until RA-diagnosis. Patients with a negative anti-CPP result (CCPoint® or ELISA) are followed up with a questionnaire after 1 and 3 y. Results: From 978 included patients, 105 (10.7%) were CCPoint® positive. 96 were tested with ELISA and 27 (28.1%) were confirmed anti-CCP positive. 9 (33.3%) were diagnosed with RA at the first RD visit (study visit 2); 4 further patients were diagnosed with RA during the follow-up (FU) period so far. Overall, 48.1% of ELISA-positive (ELISA+) patients were diagnosed with RA up to now; 11 ELISA+ patients are still in the FU period of the study. Of the 868 CCPoint® negative patients, currently, 282 have filled out a 1-year FU questionnaire; 3.5% of those reported a RA diagnosis (Table 1). As expected, clinical parameters at V2 (e.g. CRP, swollen and tender joint count) were worse in the ELISA+/RA+ group compared to the ELISA-/RA- group, but no obvious differences were detected between ELISA+ patients who were diagnosed with RA during the FU period (after V2) and ELISA-/RA- patients Table 1. Number and percentage of patients with a RA diagnosis Anti-CCP status Visit 2 Follow-up* Total Point-of-Care Test - - 3.5% (10 of 282) # 3.5% (10 of 282) # Point-of-Care Test + / ELISA - 2.9% (2 of 69) 0% (0 of 34) # 2.9% (2 of 69) Point-of-Care Test + / ELISA + 33.3% (9 of 27) 14.8% (4 of 27) 48.1% (13 of 27) $ * 1 year-questionnaire for Point-of-Care Test and ELISA negative patients or every 6 months follow-up for ELISA positive patients; # Patient-reported; $ 11 patients are still in the follow-up phase of the study Conclusion: Currently, 48.1% of anti-CCP+ (ELISA) patients have received a RA diagnosis, whereas 3.5% of the anti-CCP- (CCPoint®) received a RA diagnosis (patient reported), which underlines, that anti-CCP can be used as a marker to identify high-risk patients in GP setting. While clinical parameters are correlated with the diagnosis of RA, they are not suited for predicting future RA development alone. Anti-CCP, possibly in combination with additional parameters imaging, might increase the likelihood to early diagnose or predict RA development. Figure 1. Study overview: Patient distribution depending on anti-CCP results and RA diagnosis. Disclosure of Interests: Stephanie Dauth Grant/research support from: BMS, Michaela Köhm Grant/research support from: Pfizer, Janssen, BMS, LEO, Consultant of: BMS, Pfizer, Speakers bureau: Pfizer, BMS, Janssen, Novartis, Timm Oberwahrenbrock Grant/research support from: BMS, Ulf Henkemeier: None declared, Tanja Rossmanith Grant/research support from: Janssen, BMS, LEO, Pfizer, Karola Mergenthal Grant/research support from: BMS, Juliana J. Petersen Grant/research support from: BMS, Harald Burkhardt Grant/research support from: Pfizer, Roche, Abbvie, Consultant of: Sanofi, Pfizer, Roche, Abbvie, Boehringer Ingelheim, UCB, Eli Lilly, Chugai, Bristol Myer Scripps, Janssen, and Novartis, Speakers bureau: Sanofi, Pfizer, Roche, Abbvie, Boehringer Ingelheim, UCB, Eli Lilly, Chugai, Bristol Myer Scripps, Janssen, and Novartis, Frank Behrens Grant/research support from: Pfizer, Janssen, Chugai, Celgene, Lilly and Roche, Consultant of: Pfizer, AbbVie, Sanofi, Lilly, Novartis, Genzyme, Boehringer, Janssen, MSD, Celgene, Roche and Chugai