Elevated serum IL-6 levels predict treatment interruption in patients with moderate to severe psoriasis: a 6-year real-world cohort study

Abstract

BackgroundReal-world, primary data on the treatment of psoriasis are scarce, especially concerning the role of soluble biomarkers as outcome predictors. ObjectiveThe authors evaluated the utility of Th1/Th17 serum cytokines along with clinical characteristics as predictors of drug survival in the treatment of psoriasis. MethodsThe authors consecutively included participants with moderate to severe psoriasis who were followed up for 6 years. Baseline interferon-α, tumor necrosis factor-α, and interleukin (IL)-2, IL-4, IL-6, IL-10, and IL-17A were measured using a cytometric bead array; clinical data were assessed. The authors calculated hazard ratios (HRs) for drug survival using a Cox proportional hazards model. ResultsThe authors included 262 patients, most of whom used systemic immunosuppressants or biologics. In the multivariate model, poor quality of life measured by the Dermatology Life Quality Index (HR = 1.04; 95% CI 1.01‒1.07; p = 0.012) and elevated baseline IL-6 (HR = 1.99; 95% CI 1.29‒3.08; p = 0.002) were associated with treatment interruption. Study limitationsThe main limitation of any cohort study is the presence of confounders that could not be detected in clinical evaluation. ConclusionsPoor quality of life and elevated baseline serum IL-6 level predicted treatment interruption in patients with moderate to severe psoriasis. Although IL-6 is not the most important mediator of the inflammatory pathway in the skin environment, it is an interesting biomarker candidate for predicting psoriasis treatment response.