RT Journal Article SR Electronic T1 Haematological malignancies in patients with psoriatic arthritis overall and treated with TNF inhibitors: a Nordic cohort study JF RMD Open JO RMD Open FD EULAR SP e002776 DO 10.1136/rmdopen-2022-002776 VO 8 IS 2 A1 Rene Lindholm Cordtz A1 Johan Askling A1 Benedicte Delcoigne A1 Karin E Smedby A1 Eva Baecklund A1 Christine Ballegaard A1 Pia Isomäki A1 Kalle Aaltonen A1 Bjorn Gudbjornsson A1 Thorvardur Jon Love A1 Sella Aarrestad Provan A1 Brigitte Michelsen A1 Joseph Sexton A1 Lene Dreyer A1 Karin Hellgren YR 2022 UL http://rmdopen.bmj.com/content/8/2/e002776.abstract AB Objectives To evaluate the risk of haematological malignancies in patients with psoriatic arthritis (PsA) overall, and in relation to treatment with tumour necrosis factor inhibitors (TNFi).Methods We identified that patients with PsA starting a first TNFi from the clinical rheumatology registers (CRR) in the five Nordic countries (n=10 621) and biologics-naïve PsA patients from (1) the CRR (n=18 705) and (2) the national patient registers (NPR, n=27 286, Sweden and Denmark) from 2006 through 2019. For Sweden and Denmark, general population comparators were matched 5:1 to PsA patients on birth year, year at start of follow-up and sex. By linkage to the national cancer registers in all countries, we collected information on haematological malignancies overall, and categorised into lymphoid or myeloid types. We estimated incidence rate ratios (IRRs) with 95% CIs using modified Poisson regression for TNFi-treated versus biologics-naïve PsA patients and versus the general population adjusted for age, sex, calendar period and country.Results During 59 827 person-years, 40 haematological malignancies occurred among TNFi-treated patients with PsA resulting in a pooled IRR of 0.96 (0.68–1.35) versus biologics-naïve PsA from CRR and an IRR of 0.84 (0.64–1.10) versus biologics-naïve PsA from NPR. The IRR of haematological malignancies in PsA overall versus general population comparators was 1.35 (1.17–1.55). The estimates were largely similar for lymphoid and myeloid malignancies.Conclusions Treatment with TNFi in patients with PsA was not associated with an increased incidence of haematological malignancies. Conversely, a moderately increased underlying risk was seen in patients with PsA compared with the general population.No data are available. Due to GDPR regulations, all the data used for this study are kept within each country on encrypted servers, and are not available for the public.