Predictors for tumour necrosis factor inhibitor-induced paradoxical psoriasis in rheumatoid arthritis: an exploratory analysis informed by cross-validated random forest

We report on the predictive value of multiple clinical and social factors for the development of new-onset psoriasis within a 6-month window following tumour necrosis factor inhibitor (TNFi) use. Results on multivariable analysis indicated that simultaneous methotrexate use and male sex were associated with 9.5-fold [95% confidence interval (CI) 5.27–16.92, P < 0.001] and 2.4-fold (95% CI 1.31–4.27, P = 0.004) increased odds of developing psoriasis after first TNFi use, respectively.