Background:COMPLETE-PsA was a Canadian observational study of biologic-naïve adults with active psoriatic arthritis (PsA) treated with adalimumab (ADA) or conventional systemic disease-modifying anti-rheumatic drugs (csDMARDs) after switch from a previous conventional therapy.Objectives:To compare the impact of ADA vs csDMARDs on clinical and patient-reported outcomes due to PsA over 24 months.Methods:Eligible patients were biologic naïve adults with active PsA who required change in their treatment due to inadequate response or non-tolerance, as per treating physician judgement. Patients were enrolled between July/2011 and December/2017 and followed for a maximum 24 months. Treatment was as per routine care. Outcome measures included tender/swollen joint count (TJC/SJC), morning stiffness (min/day), patient’s global assessment of disease activity (PtGA) and pain (both 100 mm VAS), quality of life (DLQI), and functional disability (HAQ-DI). Outcome changes over time were evaluated using multivariable models adjusting for baseline measures. Achievement of modified minimal disease activity [mMDA, 5/7 of: TJC and SJC ≤1 each, psoriasis BSA ≤3%, pain ≤15 (VAS, mm), PtGA ≤20, HAQ-DI ≤0.5, and no enthesitis], and presence of enthesitis and dactylitis, were assessed descriptively. Analyses were conducted in the intent-to-treat population.Results:A total of 277 ADA and 148 csDMARD-treated patients were included in the analysis. At baseline, 61.7% of ADA and 81.1% of csDMARD patients reported concomitant methotrexate. Compared to the csDMARD group, ADA-treated patients demonstrated significantly (p<0.05) greater baseline disease severity with respect to mean (SD) joint count [TJC: 8.9 (6.2) vs. 7.4 (6.6); SJC: 7.4 (5.0) vs. 5.9 (4.6)], morning stiffness [83.5 (98.2) vs. 61.8 (77.4) min/day], PtGA [56.1 (24.1) vs. 45.1 (24.7) mm], pain [58.5 (24.3) vs. 50.1 (24.0) mm], DLQI scores [6.1 (6.9) vs. 4.3 (5.3)] and HAQ-DI [1.1 (0.6) vs. 0.8 (0.6)]. The rate of baseline mMDA was slightly lower for ADA patients (4.3% vs. 7.4%; p=0.178). Baseline prevalence of enthesitis was comparable (ADA: 28.4% vs. csDMARD: 23.4%; p=0.276), while dactylitis was significantly more prevalent for csDMARD patients (26.2% vs. 36.3%; p=0.031).Overall effect of treatment group, over 24 months, significantly (p<0.05) favored the ADA vs. csDMARD-treated patients for TJC [estimate (95%CI): -2.4 (-3.4, -1.4)] SJC [-1.8 (-2.5, -1.2)], PtGA [-3.7 (-9.3, 1.9)], DLQI [-1.5 (-2.5, -0.5)], and HAQ-DI [-0.1 (-0.2, 0.0)] (Figure 1). There was no significant difference for morning stiffness and pain.At month 24, statistically comparable (p>0.05) baseline-adjusted values (the least square means: LSM) were observed for ADA- vs. csDMARD-treated patients for TJC [LSM (95%CI): 1.8 (1.2, 2.4) vs. 3.0 (2.1, 3.8)], SJC [1.2 (0.8, 1.7) vs. 2.1 (1.5, 2.7)], morning stiffness [32.4 (19.1, 45.6) vs. 29.9 (11.1, 48.6) min/day], PtGA [31.6 (28.1, 35.2) vs. 36.9 (31.8, 41.9) mm], pain [35.3 (31.5, 39.0) vs. 38.4 (33.1, 43.7) mm], DLQI [2.9 (2.2, 3.6) vs. 2.9 (2.0, 3.8)], and HAQ-DI [0.7 (0.6, 0.8) vs. 0.9 (0.8, 1.0)].Achievement of mMDA at month 24 was reported by 34.1% and 34.9% of ADA- and csDMARD-treated patients, respectively (p=0.892). Rates of dactylitis (10.6% vs. 10.0%) and enthesitis (9.6% vs. 14.4%) were comparable in the ADA vs. csDMARDs groups respectively.Conclusion:The results of this real-world Canadian study indicate a physician selection bias for treatment with ADA for PsA patients with more severe disease burden, indicated by greater baseline disease activity and PROs. ADA-treated patients experienced a greater treatment effect over 24 months compared to csDMARD-treated patients. However, despite the greater treatment effect of ADA, residual disease burden in the two groups was comparable at 24 months.Acknowledgements:The authors wish to acknowledge JSS Medical Research for their contribution to the statistical analysis, medical writing, and editorial support during the preparation of this abstract. AbbVie provided funding to JSS Medical Research for this work.Disclosure of Interests:Majed Khraishi Speakers bureau: Speaker for AbbVie, Consultant of: Consultant for AbbVie, Grant/research support from: Principal Investigator for AbbVie, Samuel Silverberg Consultant of: Consultant for AbbVie, Janssen, and Pfizer, Yatish Setty Consultant of: Advisory Board meetings with AbbVie and Janssen, Marie-Claude Laliberté Employee of: Employee of AbbVie, Louis Bessette Speakers bureau: Speaker for Amgen, BMS, Janssen, UCB, AbbVie, Pfizer, Merck, Celgene, Lilly, Novartis, Gilead, Sandoz, Fresenius Kabi, Consultant of: Consultant for Amgen, BMS, Janssen, UCB, AbbVie, Pfizer, Celgene, Lilly, Novartis, Gilead, Sandoz, Samsung Bioepis, Fresenius Kabi, Grant/research support from: Investigator for Amgen, BMS, Janssen, UCB, AbbVie, Pfizer, Merck, Celgene, Sanofi, Lilly, Novartis, Gilead.