Oxidants, antioxidants, and the clinical course of COVID-19 disease: a prospective observational study

Microvascular damage by oxidative stress is central in the pathogenesis of generalized COVID-19 disease. Hence, a disbalance of endothelial-derived oxidative and anti-oxidative factors in COVID-19 patients can be expected, and the extent of this disbalance might correlate with disease severity.

We measured xanthine oxidase (XO), superoxide dismutase (SOD), catalase (CAT), and ischemia modified albumin (IMA) in serum samples of 166 COVID-19 patients and 238 controls. We then cathegorized the COVID-19 group further into mild, moderate, severe and lethal courses and tested these for correlation with each parameter alone, and with multi-parametric logistic regression analysis.

Compared to controls, XO was significantly lower in COVID-19 patients, SOD and CAT were significantly higher. Difference in IMA was insignificant. In the single parameter analysis, only CAT concentration was significantly correlated to disease severity. In the logistic regression analysis, XO and SOD were negatively correlated with disease severity.

Oxidative stress in COVID-19 does derive from other sources than endothelial XO. The rise in protective enzymes like SOD and CAT may be the result of enzyme induction. Since the correlation of CAT with disease severity was highest, we propose this parameter as a possible predictor for a severe clinical course.