Thiol level and total oxidant/antioxidant status in patients with COVID-19 infection

Accumulating evidence suggests that oxidative stress is closely related to the pathogenesis and severity of COVID-19 infection. Here, we attempted to compare thiol, total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) levels between COVID-19 patients who need and do not need intensive care unit (ICU) support, and determine whether these markers could be used as predictors of ICU admission.

We recruited 86 patients with COVID-19 infection and classified them into two groups according to the level of care: ICU group (n = 40) and non-ICU group (n = 46). Thiol, TAS, TOS, and OSI levels were determined and compared between the two groups.

The levels of thiol and TAS in serum were markedly lower in ICU patients than in the non-ICU patients. On the contrary, TOS and OSI levels were markedly higher. Inflammatory markers, including white blood cell, neutrophil, C-reactive protein, procalcitonin, and ferritin, were negatively correlated with the thiol and TAS, and positively correlated with the TOS and OSI. We determined that areas under the ROC curve for thiol, TAS, TOS, and OSI were 0.799, 0.778, 0.713, and 0.780, respectively.

Our results revealed that the increase in oxidative stress and decrease in antioxidant levels in COVID-19-infected patients were associated with worsening of disease. Thiol, TAS, TOS, and OSI parameters can be used to distinguish between ICU patients and those who do not, among which thiol was the best predictor of ICU requirement.