The predictors of paradoxical reactions, especially psoriasis, to biologic therapy—findings from the TReasure database: a 5-year follow-up study

To assess the clinical characteristics, predictive factors, and practical algorithms of paradoxical reactions (PRs), specifically paradoxical psoriasis (PP).The TReasure database, is a web-based prospective observational cohort comprised of patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) from 17 centers around Turkey since 2017. A cohort study and a case-control study nestled within the cohort were identified.2867 RA and 5316 SpA patients were evaluated. The first biologic agent was found to have caused PR in 60% of the 136 patients (1.66%) who developed the PR. The median time interval between the PRs and biological onset is 12 months (range 1-132, mean 21 months). The most common type of PP, constituting 92.6% of PR, was pustular (60.3%) and palmoplantar (30.9%). Adalimumab (30.9%), infliximab (19%), and etanercept (17.4%) were the most common agents causing the PP. In the treatment of most PP patients (73.2%), switching biologic agents was favored, with tumor necrosis factor inhibitor (TNFi) chosen in 46.03% and non-TNFi in 26.9%. The three most frequently selected drugs were etanercept (24.6%), secukinumab (9.5%), and adalimumab (8.7%). Only 5.17% of patients who switched to another TNFi showed progression. Sulfasalazine, hydroxychloroquine and leflunomide use odds ratios were significantly higher in RA controls than PP patients (p= 0.033, OR = 0.15; p= 0.012 OR = 0.15; p= 0.015, OR = 0.13). In the PP group with SpA, the number of smokers were significantly higher (p= 0.003, OR: 2.0, 95% CI: 1,05-3,81).Unlike the class effect, the response of patients who were shifted to another TNFi was favorable.