Association of total oxidant status, total antioxidant status, and malondialdehyde and catalase levels with psoriasis: a systematic review and meta-analysis

Although oxidative stress plays a major role in psoriasis, the association between oxidative stress biomarker levels and psoriasis in humans remains controversial. Relevant articles were retrieved by searching the following databases: PubMed, Web of Science, and EMBASE, without any time limit (updated March 10th, 2019). The pooled weighted mean difference (WMD) and 95% confidence interval (CI) for the total oxidant status (TOS), total antioxidant status (TAS), malondialdehyde (MDA), and catalase (CAT) were calculated for each study. Heterogeneity test, publication bias analysis, and sensitivity analysis were performed. A total of 28 case-control studies, containing a combined total of 2724 subjects (1485 psoriasis patients and 1239 healthy controls), were enrolled in this meta-analysis. The combined results showed a significant difference in the TAS levels (WMD = − 0.213 mmol/L, p < 0.001, 95% CI = − 0.216 to − 0.165), TOS levels (WMD = 2.196 μmol/L, p < 0.001, 95% CI = 1.667 to 2.726), MDA levels (WMD = 1.854 nmol/L, p < 0.001, 95% CI = 1.494 to 2.215), and CAT levels (WMD = − 22.341 kU/L, p = 0.008, 95% CI = − 38.934 to − 5.748) between psoriasis patients and controls. Moreover, the combined results showed a significant difference in the TAS, MDA, and CAT levels in patients with mild vs. moderate psoriasis and moderate vs. severe psoriasis. TAS and CAT levels in psoriasis patients were significantly lower than in healthy controls, whereas the TOS and MDA levels were significantly higher. Furthermore, the TAS, MDA, and CAT levels are associated with the severity of disease. These results indicate that redox imbalances play a major role in the pathogenesis of psoriasis.