AB0301 ANTIMICROBIAL USE IS HIGH IN PATIENTS WITH INFLAMMATORY ARTHRITIDES, AND FURTHER INCREASES WITH FIRST-LINE TNFI THERAPY – NATIONWIDE RESULTS
Authors: Aron H. Bjornsson, Kristin P. Sigurbjornsdottir, Olafur Palsson, Thorvardur Jon Love, Petur S. Gunnarsson, Mar Kristjansson, Björn Gudbjornsson
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> 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. <h3>Objectives</h3> 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-naïve patients. <h3>Methods</h3> All patients with inflammatory arthritides who are treated with biologic DMARDs in Iceland are registered in ICEBIO, a nationwide registry. On February 1<sup>st</sup> 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). <h3>Results</h3> 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&lt;0.01). The patient group received more DID of antimicrobials following the start of TNFi, with a statistically significant increase in PsA (33.9 to 45.2; p&lt;0.01), AS (37.2 to 46.8; p&lt;0.01) and nonsignificant in RA (46.8 to 49.7; p=0.066). Antibacterial use increased from 115 DID to 137 DID for the whole group, most prominently in the PsA and AS groups (Table I). Antifungal use increased in patients with RA and antiviral use in RA and PsA (Table I). <h3>Conclusion</h3> 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. <h3>Disclosure of Interests</h3> 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, Björn Gudbjornsson: None declared