OP0257 RISK OF HAEMATOLOGICAL MALIGNANCY IN PATIENTS WITH PSORIATIC ARTHRITIS, OVERALL AND IN RELATION TO TNF INHIBITORS - A NORDIC COHORT STUDY

• Published in: Annals of the Rheumatic Diseases
• Main Authors: Cordtz, R., Askling, J., Delcoigne, B., Ekström Smedby, K., Baecklund, E., Ballegaard, C., Isomäki, P., Aaltonen, K., Gudbjornsson, B., Love, T., Provan, S. A., Michelsen, B., Sexton, J., Dreyer, L., Hellgren, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMJ 2022
• Subjects: General Biochemistry, Genetics and Molecular Biology; Immunology; Immunology and Allergy; Rheumatology; Norway; Iceland
• Online Access: http://dx.doi.org/10.1136/annrheumdis-2022-eular.403; https://syndication.highwire.org/content/doi/10.1136/annrheumdis-2022-eular.403

Background Several autoimmune inflammatory diseases, including rheumatoid arthritis (RA), are associated with increased risk of malignant lymphomas. There is also a longstanding concern of lymphoma development with tumour necrosis factor inhibitor (TNFi) treatment, but most studies in RA to date do not indicate an additionally increased risk. Corresponding studies in psoriatic arthritis (PsA), both with respect to the underlying risks, and risks in relation to treatment with TNFi, are limited. Data on myeloid malignancies in PsA are scarce. Objectives To estimate the risk of haematological malignancy overall and by lymphoid and myeloid types in TNFi treated versus (vs.) biologics-naïve patients with PsA across the five Nordic countries. Additionally, we investigated the underlying risk of haematological malignancies in PsA as compared to the general population. Methods We identified patients with PsA starting a first ever TNFi from the clinical rheumatology registers (CRR) in Sweden (SE), Denmark (DK), Norway (NO), Finland (FI), and Iceland (ICE) from 2006 through 2019 (n=10 621). We identified biologics-naïve patients with PsA from a) the CRR (n=18 705, all countries) and b) the national patient registers (NPR, n=27 286, SE and DK only). To estimate the underlying risk of haematological malignancy in PsA, we randomly sampled general population comparators in SE and DK matched on year of birth, sex, and calendar year at start of follow-up, to the patients with PsA. Through linkage to the mandatory national cancer registers in all five countries, we collected information on haematological malignancy overall, and categorised into lymphoid or myeloid types. By applying a modified Poisson regression, we estimated pooled incidence rate ratio (IRR) with 95% confidence intervals (CI) for TNFi treated vs. biologics-naïve PsA and for PsA vs. the general population, adjusted for age (18-55, 56-65, 66-70, >70 years), sex, calendar period (2006-2010, 2011-2019) and country, and using robust standard errors. Results We ...