Oxidative stress markers in blood in systemic sclerosis: A meta-analysis

Objectives: The purpose of this study is to clarify the relationship between systemic sclerosis (SSC) and oxidative stress markers in blood.Methods: We conducted a systematic literature search of databases, including PubMed and Embase, for studies reporting circulating oxidative stress markers in patients with SSC and controls published from 1980 to December 2015. Standardized mean differences (SMDs) and 95% confidence intervals (95%CI) were calculated.Results: Of the 1076 articles initially retrieved, 47 were included in our meta-analysis including 12 oxidative stress markers. The concentrations of nitric oxide (SMD=0.77; 95%CI: 0.18, 1.36; p=0.01), malondialdehyde (SMD=1.63; 95%CI: 1.03, 2.24; p=0.000), asymmetric dimethylarginine (SMD=0.51; 95%CI: 0.12, 0.91; p=0.011), and ROOH (SMD=3.37; 95%CI: 0.28, 6.46; p=0.033) in the blood of patients with SSC were higher than those of the control group, whereas the concentrations of superoxide dismutase (SMD=-1.11; 95%CI:-1.57, -0.65; p=0.000) and vitamin C (SMD=-1.12; 95%CI:-1.51,-0.73; p=0.000) were lower than in the control group.Conclusions: The oxidative stress markers in blood for patients with SSC were aberrant, indicating the imbalanced states of oxidation and antioxidation in SSC.