POS0580 COMORBIDITY BURDEN IS HIGH IN RHEUMATOID ARTHRITIS AND SPONDYLOARTHRITIS PATIENTS STARTING BIOLOGICS AND PREDICTS THE INCIDENCE OF SERIOUS ADVERSE EVENTS DURING THERAPY
Authors: I. Flouri, A. Repa, N. Avgustidis, N. Kougkas, A. Eskitzis, A. Molla Ismail Sali, S. Pitsigavdaki, K. Pateromichelaki, E. Kalogiannaki, M. Terizaki, G. Bertsias, P. Sidiropoulos
Journal: Annals of the Rheumatic Diseases (2021)

Background: There is limited information on the burden of comorbidities in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) in real-world clinical practice and its impact on the incidence of serious adverse events (SAE) during biologic disease-modifying anti-rheumatic drug (bDMARD) therapy. Objectives: To evaluate the number of comorbidities in patients with RA and SpA initiating a bDMARD in everyday clinical practice and to explore its association with the occurrence of a SAE during therapy. Methods: Prospective study of all patients who start any bDMARD treatment in a tertiary centre University Hospital. All comorbidities and SAEs (AEs necessitating hospitalization or resulting in significant incapacity/death) are registered by treating physicians. Comorbidities’ number was evaluated using two different indices: total comorbidities count (CC) and Rheumatic Disease Comorbidity Index (RDCI). Statistical analysis was performed using multinomial logistic and Cox regression models. Results: A total of 799 patients were analysed, of which 428 (54%) had ≥3 comorbidities (Table 1). Comorbidity burden was higher in RA, however in multivariable analyses, comorbidities were not significantly associated with diagnosis, but mainly with increasing patient age. Patients received 1701 bDMARD treatments. During a follow-up of 4019 patient-years, 198 patients (RA:134, SpA:64) had a total of 295 SAE (RA: 217, SpA:78). Each one additional comorbidity in CC index was resulting in 16% increased adjusted risk for the first SAE [HR (95%CI) = 1.16 (1.12-1.20), p&lt;0.001], and each additional comorbidity of the RDCI index was resulting in 28% increased risk [HR (95%CI) = 1.28 (1.20-1.37), p&lt;0.001]. Other baseline independent predictors of the first SAE were greater age [HR=1.04, p&lt;0.001] and use of corticosteroids [HR=1.42, p=0.006]. Table 1. Biologic treatments and clinical characteristics at baseline Patients, Ν Total RA SpA p 799 501 298 Females, Ν (%) 535 (67) 404 (81) 131 (44) &lt;0.001 Age, median (IQR) έτη 55 (45-65) 60 (51-68) 46 (36-54) &lt;0.001 Disease duration, median (IQR) έτη 6.0 (2.5-13) 5.4 (3-11) 7.4 (2.0-15) &lt;0.001 Comorbidities count, median (IQR) 3 (1-5) 3 (2-6) 2 (1-4) &lt;0.001 Patients with no comorbidities, Ν (%) 103 (13) 43 (9) 60 (20) &lt;0.001 Patients with 1 comorbidity, Ν (%) 134 (17) 77 (15) 57 (19) 0.172 Patients with 2 comorbidities, Ν (%) 134 (17) 76 (15) 58 (19,5) 0.118 Patients with ≥3 comorbidities, Ν (%) 428 (54) 305 (61) 123 (41) &lt;0.001 RDCI, median (IQR) 1 (0-2) 2 (0-3) 1 (0-2) &lt;0.001 Patients with RDCI = 0, Ν (%) 267 (33) 128 (25.5) 139 (47) &lt;0.001 Patients with RDCI = 1, Ν (%) 185 (23) 119 (24) 66 (22) 0.665 Patients with RDCI = 2, Ν (%) 163 (20) 113 (23) 50 (17) 0.057 Patients with RDCI ≥ 3, Ν (%) 184 (23) 141 (28) 43 (14) &lt;0.001 Total bDMARDs initiated by patients, Ν 1701 1098 603 Co-administered methotrexate, Ν(%) 946 (56) 674 (61) 272 (45) &lt;0.001 Co-administered corticosteroids, Ν (%) 493 (29) 397 (36) 96 (16) &lt;0.001 DAS28, median (IQR) (in RA and perSpA) 5.8 (4.9-6.6) 5.8 (5.0-6.6) 5.4 (4.2-6.3) &lt;0.001 BASDAI, median (IQR) (in axSpA) - - 5.6 (4.5-7.0) Conclusion: Patients with RA and SpA initiating a bDMARD treatment in real-world clinical practice have a significant comorbidity burden which increases with age and is an independent predictor for an SAE during therapy. Acknowledgements: This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Reinforcement of Postdoctoral Researchers - 2nd Cycle” (MIS-5033021), implemented by the State Scholarships Foundation (ΙΚΥ). Disclosure of Interests: None declared