AB1534 A VALIDATION OF REGISTER DERIVED DIAGNOSES OF INTERSTITIAL LUNG DISEASE IN PATIENTS WITH INFLAMMATORY ARTHRITIS. DATA FROM NOR-DMARD

Background There is a lack of knowledge concerning the validity International classification diseases (ICD) diagnoses extracted from health registers although this information often used in epidemiological studies. Objectives To assess register derived interstitial lung disease (ILD) patients with rheumatic diseases, using ILD identified on computed tomography (CT) and/or medical journal as gold standard. Methods The Norwegian Anti-Rheumatic Drug Register (NOR-DMARD) multi-centre prospective observational study that includes diagnosis inflammatory arthritis who started treatment modifying anti-rheumatic drugs. NOR-DMARD was linked to Patient Registry (NPR) and Cause Death Registry. We searched both for ICD-10 codes (J70, J84 or J99) CTs participants at four hospitals. taken three months before within one year after first registries were considered relevant study. An expert thoracic radiologist (FA) scored all examinations according presence categorised finding into; no ILD, possible confirmed ILD. Possible CT images re-examined by second (TMA). In addition, records given specialist clinicians several occasions. Presence assessed available CTs, registry ICD-code ≥2 time points across subgroups. Results 80 cases an (ICD-10 n (%); J70 10 (12.5), 52 (65.0) J90 18 (22.5)). 72/80 (90%) patients, 60/72 (83%) pre-specified time-window. 31/80 (38.8%) 9/80 (11.3%) only. validated 34 (56.7%) 60 time-period 28/43 (65.1%) had received code HRCT (Table 1). 20 (69.9%) 29 group diagnoses. not most frequently under investigations respiratory symptoms 20/38 (52.6%). Conclusion registry-based must be carefully Table 1. Positive predictive value patient cohorts progressive selection criteria Number cohort (%) 42 (52.5) prespecified (56.7) 43 two more 28 (65.1) 45 ICD10: 2 (33.3) ICD10 (69.0) J99 6 (75.0) Footnotes: ILD: REFERENCES: NIL. Acknowledgements: Disclosure Interests Sella Aarrestad Provan Consultant of: Boehringer Ingelheim, Novartis, Grant/research support from: Fredrik Ahlfors: None declared, Gunnstein Bakland Speakers bureau: Abbvie, UCB, Pfizer, MSD og Celgene, Hu Ye: Eirik kristianslund: Tore K. Kvien Grünenthal, Sandoz, AbbVie, Amgen, Celltrion, Gilead, UCB , BMS, Galapagos, UCB. Ikdahl: Trond M Aaløkken Anna-Maria Hoffmann-Vold Jannsen, Medscape, Merck Sharp & Dohme Roche, ARXX, Genentech, Jannsen.