BACKGROUND: Metabolic syndrome, a risk factor of cardiovascular disease, is more common in patients with psoriasis than in the general population. Circulating adipokine concentrations are altered in patients with psoriasis and are suggested to represent the pathophysiological link between psoriatic lesions and metabolic alterations.OBJECTIVES: To perform a systematic review of the literature for studies that investigated possible differences in circulating levels of leptin, adiponectin or resistin in patients with psoriasis before and after any treatment intervention, and to meta-analyse the best evidence available.METHODS: A search was conducted in three databases (PubMed, Central and Embase). Eligible for the review were studies that assessed leptin, adiponectin or resistin concentrations in patients with psoriasis before and after any topical or systemic treatment.RESULTS: After treatment, blood concentrations of leptin were similar to those before treatment [standardized mean difference (SMD) 0·06, 95% confidence interval (CI) -0·09 to 0·20], with no heterogeneity among studies (I = 0%, P = 0·88). After treatment, blood concentrations of adiponectin were similar to those before treatment (SMD -0·14, 95% CI -0·34 to 0·05), with significant heterogeneity among studies (I = 36·8%, P = 0·032). After treatment, blood concentrations of resistin were significantly lower than those before treatment (SMD 0·50, 95% CI 0·20-0·79), with significant heterogeneity among studies (I = 61·4%, P < 0·001).CONCLUSIONS: There is no evidence that treatment for psoriasis modifies leptin and adiponectin concentrations. However, treatment intervention reduces resistin concentrations, a finding that is expected to be of clinical importance.