POS0313 INCIDENCE AND PREVALENCE OF POLYAUTOIMMUNITY IN SEROPOSITIVE COMPARED WITH SERONEGATIVE PATIENTS WITH RHEUMATOID ARTHRITIS: A NATIONWIDE COHORT STUDY

Background: Rheumatoid arthritis (RA) is categorized as seropositive or seronegative referring to the presence absence of IgM rheumatoid factor (IgM-RF) and/ anti-citrullinated protein antibodies (ACPA). Patients with an autoimmune disease are more likely develop additional conditions than individuals without pre-existing disease. Objectives: The aims this study were examine patterns polyautoimmunity in compared patients recent-onset RA. Methods: was register-based and used nationwide DANBIO register (identification (<1 year) seropositive, ICD-10 M05, seronegative, M06, RA patients) linked Danish National Patient Registry Prescription obtain information on diseases (see Table 1 for conditions). 1. Characteristics, prevalence, incidence incident patients. Seropositive Seronegative N 7983 4534 Age years 59.4 (48.6 69.1) 63.0 (51.5 72.3) Women 5476 (69 %) 2856 (63 HAQ-DI 0.857 (0.375 1.375) 0.875 DAS28-CRP 4.3 (3.3 5.2) 4.6 (3.6 5.5) CRP, mg/mL 10 (4 23) (3 26) VAS physician, 0-100mm 27 (15 45) 30 (16 47) Treated methotrexate 86 % 84 -other csDMARD, 24 -Biological DMARD, 5 6 Smoking status: Current / previous never unknown, 13 11 17 59 9 23 Prevalence diabetes mellitus type thyroid inflammatory bowel 549 (10.6 1.4 6.7 349 (12.8 1.5 7.8 sex adjusted odds ratio 0.79 (0.71 0.89) (ref.) Incident cases 373 (4.7 242 (5.3 Adjusted hazard 0.86 1.05) Continuous variables shown median interquartile ranges. Autoimmune included: (redeemed prescriptions ATC=H03A); (ICD-10 diagnosis E10 combined redeemed insulin, ATC=A10A); pernicious anaemia (D51.0); haemolytic (D59.1); idiopathic thrombocytopenic purpura (D69.3); adrenalitis (E27.1B); multiple sclerosis (G35); neuromyelitis optica (G36.0); Guillain-Barré syndrome (G61.0); myasthenia gravis (G70); (K50-1); primary biliary cirrhosis (K74.3); sclerosing cholangitis (K83.0); hepatitis (K75.4); celiac (K90.0); pemphigus vulgaris (L10.0); bullous pemphigoid (L12.0); dermatitis herpetiformis (L13.0); alopecia areata (L63); vitiligo (L80); lichen (L90.0); chronic interstitial cystitis (N30.1). Using age logistic regression analysis, (OR) prevalent at time calculated. To estimate (HR) developing yet another after diagnosis, cause-specific Cox models performed. Several sensitivity analyses carried out including alternative exposure outcome definitions. Results: In total, 12,517 included. groups similar terms characteristics DMARD treatment, but younger included women, see had OR (95% CI 0.71-0.89) baseline patients, whereas 5-year HR 0.71-1.05) polyautoimmunity. results remained all analyses. Conclusion: a slightly lower prevalence somewhat surprising, very robust, thus raises question if fact “more autoimmune” despite (identified) autoantibodies. Acknowledgements: We acknowledge departments rheumatology contributing registry. Disclosure Interests: Amalie Hagelskjær: None declared, René Cordtz: Sofie Bliddal: Anders Sandermann Mortensen: Salome Kristensen: Claus Henrik Nielsen: Ulla Feldt-Rasmussen: Christian Torp-Pedersen: Lene Dreyer Grant/research support from: Grants from BMS, Galderma, Eli Lilly