Psoriasis and metabolic syndrome: a systematic review and meta-analysis of observational studies.

BACKGROUND: Increasing population-based studies have suggested a relationship between psoriasis and metabolic syndrome. OBJECTIVE: The objective of this study was to perform a systematic review and meta-analysis that synthesizes the epidemiologic associations between psoriasis and metabolic syndrome. METHODS: We searched for observational studies from MEDLINE, EMBASE, and Cochrane Central Register from Jan 1, 1980 to Jan 1, 2012. We applied the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines in the conduct of this study. RESULTS: We identified 12 observational studies with a total of 1.4 million study participants fulfilling the inclusion criteria, among whom 41,853 were patients with psoriasis. Based on random-effects modeling of cross-sectional and case-controlled studies, the pooled odds ratio (OR) for metabolic syndrome among patients with psoriasis was 2.26 (95% confidence interval [CI] 1.70-3.01) compared with the general population. Visual inspection of a funnel plot and formal analysis with the Egger test suggested publication bias and absence of small studies in the published literature (P = .03). A dose-response relationship was also observed between psoriasis severity and prevalence of metabolic syndrome. LIMITATIONS: No studies to date have assessed incidence of metabolic syndrome among patients with psoriasis. CONCLUSIONS: Compared with the general population, psoriasis patients have higher prevalence of metabolic syndrome, and patients with more severe psoriasis have greater odds of metabolic syndrome than those with milder psoriasis.