Assessment of oxidative stress markers in elderly patients with SARS-CoV-2 infection and potential prognostic implications. An observational study

The aim of the study was to evaluate the correlation of plasma levels of thiobarbituric acid reactive substances (TBARS) and reduced thiols with morbidity, mortality and immune response in SARS-CoV-2 infection. This was an observational study that included inpatients with SARS-CoV-2 infection greater than 65 years old. Individuals were followed up until 12 months after hospital discharge. Demographic, clinical and laboratory variables were collected. Plasma levels of TBARS and reduced thiols were quantified as a measure of lipid and protein oxidation, respectively. Events of interest (fatal and non-fatal) were quantified at hospital discharge, third, sixth and twelfth-month post-discharge. The outcomes were differences in oxidative stress markers between groups of interest and time to a negative RT-qPCR and to significant anti-SARS-CoV-2 IgM titers. There were 61 patients (57% women) with a mean age of 83 years old. Patients with higher levels of TBARS and lower levels of reduced thiols had more risk of fatal and non-fatal events between admission and the first 12 months post-discharge. The presence of any event (fatal or non-fatal) at the end of the first 12 months post-discharge was correlated with TBARS levels, anti-SARS-CoV-2 IgM titers, lactate dehydrogenase, platelet count and neutrophil and lymphocyte count. We found a correlation between plasma reduced thiols and time to achieve significant anti-SARS-CoV-2 IgM titers. Assessment of some parameters related to oxidative stress could help to identify groups of patients with a higher risk of morbidity and mortality during and after SARS-CoV-2 infection.