AB0301 ANTIMICROBIAL USE IS HIGH IN PATIENTS WITH INFLAMMATORY ARTHRITIDES, AND FURTHER INCREASES WITH FIRST-LINE TNFI THERAPY – NATIONWIDE RESULTS

Background Infections are well-known adverse effects of tumor necrosis factor inhibitors (TNFi) and increased hospitalization rates due to infections have also been reported. To our knowledge, this is the first study to report the effect of TNFi initiation on outpatient antimicrobial prescription patterns. Objectives To investigate the use of antimicrobial agents (antibacterials, antifungals and antivirals; excluding antimycobacerials) in patients with rheumatoid arthritis, psoriatic arthritis, and axial spondyloarthritis in relation to the initiation of the first TNFi in biologic-naive patients. Methods All patients with inflammatory arthritides who are treated with biologic DMARDs in Iceland are registered in ICEBIO, a nationwide registry. On February 1st 2016, ICEBIO contained information on 1058 individuals. The Icelandic Directorate of Health operates the Icelandic Medicine Database (IMD), a registry that includes over 95% of all filled drug prescriptions in Iceland. From the IMD, filled antimicrobial prescriptions were extracted two years before and two years after the initiation of first-line TNFi therapy for all patients in ICEBIO with rheumatoid arthritis (RA; n=366), psoriatic arthritis (PsA; n=250) and axial spondyloarthritis (AS; n=218). As controls, five individuals, age and sex matched, for the same calendar time were randomly selected. Antimicrobial use was determined from defined daily dose per 1000 capita (DID). Results The use of antimicrobials prior to TNFi treatment was greater in the patient group when compared to controls (mean 43 DID vs 21 DID; p Conclusion Patients with active chronic arthritidies use statistically significantly more antimicrobials two years antedating TNFi treatment compared to controls. TNFi treatment further increases antimicrobial use in this patient population, especially in patients with PsA and AS. Meanwhile, antifungal use increased in RA and antiviral use increased in both RA and PsA. Further analysis needs to be done on the effect of co-medicines such as glucocorticoids, DMARDs and disease activity. Disclosure of Interests Aron H Bjornsson: None declared, Kristin P Sigurbjornsdottir: None declared, Olafur Palsson: None declared, Thorvardur Jon Love Consultant for: Received reimbursment from Celgene for speaking about guidelines for the treatment of psoriatic arthritis, Petur S Gunnarsson: None declared, Mar Kristjansson: None declared, Bjorn Gudbjornsson: None declared