Risk of developing psoriatic arthritis in patients with psoriasis initiating treatment with different classes of biologics

Objectives: To investigate the risk of psoriatic arthritis (PsA) in plaque psoriasis (PsO) patients receiving different classes of biologics. Methods: A retrospective observational study involving consecutive bionaïve PsO patients starting biologic treatment was performed. We compared the occurrence of PsA by the class of the biologic (tumour necrosis factor [TNF], interleukin [IL]-17, or IL-23 inhibitors) using inverse probability of treatment weighting (IPTW) in the setting of multiple treatments to balance pretreatment covariates across cohorts and thus adjust for potential confounders. An IPTW Cox regression model was used to estimate hazard ratios (HRs) of PsA for IL-17 and IL-23 inhibitors versus TNF inhibitors. Results: In total, 622 patients, 430 (62.4%) males, mean ± SD age 46.9 ± 12.9 years, were included. They have been treated with TNF (n = 317, 50.9%), IL-17 (n = 164, 26.4%) or IL-23 inhibitors (n = 141, 22.7%) and followed for 2510 person-years (a mean of 4.1 ± 2.1 years per person). TNF, IL-17, and IL-23 inhibitor cohorts had a total of 1569, 486, and 455 person-years of follow-up. A total of 60 (10%) out of 622 patients on biologic therapy developed incident PsA during the observation period: 45 (14.2%) in the TNF, 9 (5.5%) in the IL-17, and 6 (4.3%) in the IL-23 inhibitor cohorts. After IPTW, the 3 treatment cohorts were well-balanced, and the HRs of PsA were 0.63 (95% CI, 0.38-1.05) for IL-17 and 0.57 (95% CI, 0.34-0.96) for IL-23 compared with the TNF treatment group. Conclusions: The risk o