Oxidative Stress Biomarkers and Their Association with Mortality among Patients Infected with SARS-CoV-2 in Mexico

Background. Activation of the immune system response is associated with the generation of oxidative stress (OS). Several alterations are involved in OS, such as excessive production of reactive oxygen species (ROS) and decreased antioxidant activity, which together lead to an imbalance in redox status. The role of OS during SARS-CoV-2 infection is not fully understood. The aim of this study was to determine OS biomarkers and assess their usefulness as a predictor of mortality in COVID-19 patients. Methods. Baseline characteristics and serum samples were collected from hospitalized COVID-19 patients and compared with healthy controls. The serum OS biomarkers, including malondialdehyde (MDA) and total antioxidant capacity (TAC), were assessed by spectrophotometric and oxygen radical absorbance capacity (ORAC) methods, respectively. Results. A total of 152 individuals were analyzed (COVID-19 patients vs. healthy controls). Compared with healthy controls (n=76), patients infected with SARS-CoV-2 (n=76) presented higher levels of MDA (p < 0.001) and decreased TAC (p < 0.001). A total of 37 (49%) patients with COVID-19 died. The area under the receiver operating characteristic (ROC) curve (AUC) estimated that the combination of the OS biomarkers (MDA+TAC) (AUC=0.6394, p=0.037) was a significant predictor of mortality. A higher level of MDA was associated with mortality (HR, 1.05, 95% CI, 1.00-1.10, p=0.045). Conclusion. This study concludes that OS is increased in patients with COVID-19 and is associated with mortality. To our knowledge, this is the first evidence of the expression of OS biomarkers and their association with mortality among the Mexican population.