Supplementary Material for: Serum Leptin, Resistin, and Adiponectin Concentrations in Psoriasis: A Meta-Analysis of Observational Studies

<p><b><i>Background:</i></b> Psoriasis is an immune-mediated, inflammatory disease. Adipokines contribute to the regulation of immune-mediated processes and inflammation. <b><i>Objective:</i></b> The aim of our study was to systematically review the literature for studies that have evaluated the circulating concentrations of adipokines in patients with psoriasis and controls and to meta-analyze the best evidence available. <b><i>Methods:</i></b> Eligible were studies that have assessed leptin, resistin, or adiponectin concentrations in psoriatic patients and a reference group. The study was conducted in adherence with the PRISMA standards. <b><i>Results:</i></b> Psoriatic patients had higher leptin concentrations compared to controls (random effects model, mean difference, MD = 5.64 ng/mL, 95% CI: 3.00-8.29, <i>p</i> < 0.0001). Heterogeneity among studies was high (<i>I</i><sup>2</sup> = 95.9%). Psoriatic patients had higher resistin concentrations compared to controls (MD = 4.66 ng/mL, 95% CI: 2.62-6.69, <i>p</i> < 0.0001). Heterogeneity was high (<i>I</i><sup>2</sup> = 99.2%). Finally, psoriatic patients had lower adiponectin concentrations compared to controls (MD = -1.87 μg/mL, 95% CI: -2.76 to -0.98, <i>p</i> < 0.0001). Heterogeneity was high (<i>I</i><sup>2</sup> = 95.9%). <b><i>Conclusion:</i></b> The study supported the hypothesis that leptin and resistin concentrations are higher and adiponectin concentrations are lower in patients with psoriasis compared to controls. Hereby, the suggested pathogenic link between psoriasis and metabolic syndrome/obesity is reinforced and the role of comorbidities in psoriasis is highlighted.</p>