OP0222 THE INCIDENCE OF INTERSTITIAL LUNG DISEASE IN PSORIATIC ARTHRITIS COMPARED TO RHEUMATOID ARTHRITIS. DATA FROM OVER 89 000 BDMARD TREATMENT COURSES DERIVED FROM FIVE NORDIC REGISTERS

Background: Interstitial lung disease (ILD) is an established extra-articular manifestation of rheumatoid arthritis (RA). Few studies have investigated the prevalence of ILD in patients with psoriatic arthritis (PsA). Methotrexate (MTX) is frequently used in the treatment of both RA and PsA and has been suggested to be a risk factor for the development of ILD. It is of interest to understand the interaction between disease and treatment in the development of ILD. Objectives: To compare the incidence of ILD between patient with PsA and RA treated with biologic disease modifying antirheumatic drugs (bDMARDS), with or without MTX as a co-medication. Methods: Cohorts of patients with RA and PsA starting bDMARD were identified in Nordic registers (Danish nationwide clinical register for patients with RA (DANBIO), Register on antirheumatic and biological therapy in Finland (ROB-FIN), Icelandic nationwide database of biologic therapy (ICEBIO), Norwegian Antirheumatic Drug Register (NOR-DMARD), and the Swedish Rheumatology Quality Register (SRQ)). Linkages to the National Patient Registers and to the Cause of Death Registers were performed in each country to identify cases of ILD. Each individual patient could contribute several treatment courses. ILD was identified as hospital or death certificate ICD10 codes of ILD (J84.1, J84.8, J84.9, J70.2, J70.3, J70.4, J99.0, J99.1, J99.8) given during the follow-up period which was defined as the treatment course duration, plus a 30-day wash-out period added to the end of treatment course period. MTX co-medication was specified as use of MTX at the start of bDMARD. Incidence rates (IR) for any ILD were calculated per 1000 person years at risk (PYR) for each country. The five cohorts were pooled and incidence rate ratios (IRR) for PsA vs. RA were calculated. Hazard ratios (HR) for any ILD in PsA vs. RA were estimated in Cox regression models adjusted for age, gender and repeated observations, and stratified for the use of MTX co-medication. Results: Overall 47 987 individual patients representing 89 239 bDMARD treatment courses and contributing 201 279 PYR were included in the study (Table 1). Methotrexate was reported as comedication in 29 916 (33.5 %) of the treatment courses (PsA vs. RA, 30.4 % vs 34.5 %). 970 cases of ILD were identified during the follow-up period. The risk of ILD was consistently lower in patients with PsA compared to patients with RA in all countries. In models stratified for co-medication the HR for ILD in PsA vs. RA was 0.34 (0.21-0.57) in patients treated with MTX and 0.26 (0.18-0.36) in patients not treated with MTX. Conclusion: In these preliminary analyses, the incidence of ILD is lower in bDMARD treated PsA vs. RA patients, irrespective of co-medication with MTX. This indicates that the clinician should consider the rheumatological diagnosis when assessing the risk for future ILD in patients treated with bDMARDs and MTX. Acknowledgements: Partly funded by NordForsk and FOREUM Disclosure of Interests: Sella Aarrestad Provan Consultant of: Novartis, Grant/research support from: Boehringer-Ingelheim, Brigitte Michelsen: None declared, Lotta Ljung: None declared, Thorarinn Jonmundsson: None declared, Bjorn Gudbjornsson Speakers bureau: Amgen and Novartis, Daniela Di Giuseppe: None declared, Merete Lund Hetland Speakers bureau: Orion Pharma, Biogen, Pfizer, CellTrion, Merck and Samsung Bioepis, Consultant of: Eli Lilly, Grant/research support from: BMS, MSD, AbbVie, Roche, Novartis, Biogen and Pfizer, Guðrun Bjork Reynisdottir: None declared, Bente Glintborg: None declared, Eirik kristianslund: None declared, Heikki Relas: None declared, Kalle Aaltonen: None declared, Dan Nordstrom Speakers bureau: Abbvie, BMS, Celgene, Eli Lilly, MSD, Novartis, Pfizer, Roche and UCB., Consultant of: Abbvie, BMS, Celgene, Eli Lilly, MSD, Novartis, Pfizer, Roche and UCB., Tore K. Kvien Speakers bureau: Amgen, Celltrion, Egis, Evapharma, Ewopharma, Hikma, Oktal, Sandoz, Sanofi., Consultant of: AbbVie, Amgren, Biogen, Celltrion, Eli Lilly, Gilead, Mylan, Novartis, Pfizer, Roche, Sandoz, Sanofi., Johan Askling Grant/research support from: Abbvie, BMS, Eli Lilly, Merck, Pfizer, Roche, Samsung Bioepis, and Sanofi