Oxidative stress and inflammation play central roles in the immunopathogenesis of COVID‐19. In this study, we investigated whether circulating carotenoids, retinol, and vitamin E metabolites can distinguish COVID‐19 patients from healthy controls and discriminate disease severity. We analyzed 44 hospitalized COVID‐19 patients (23 with moderate disease and 21 with severe disease) and 39 healthy controls recruited from the same hospitals. Plasma concentrations of individual carotenoids, retinol, total vitamin A, vitamin E (γ‐tocopherol, α‐tocopherol), retinol‐binding protein 4 (RBP4), transthyretin (TTR), complete blood count parameters, and clinical chemistry and inflammatory markers were determined and statistically analyzed. Compared with healthy controls, COVID‐19 patients had significantly lower concentrations of vitamin E, retinol, total vitamin A, lutein, total carotenoids, and TTR and higher levels of inflammatory markers. In multivariate logistic regression, the RBP4/total vitamin A ratio, γ‐tocopherol, and ferritin emerged as independent factors differentiating COVID‐19 patients from healthy controls. Within the patient group, antioxidant micronutrient levels did not differ significantly between moderate and severe COVID‐19, whereas inflammatory markers, such as C‐reactive protein, ferritin, and the neutrophil‐to‐lymphocyte ratio, increased with severity. These data indicate that although carotenoids, vitamin A, and vitamin E are markedly depleted during COVID‐19, they do not stratify disease severity, whereas the RBP4/total vitamin A ratio, γ‐tocopherol, and ferritin may serve as useful biomarkers for distinguishing COVID‐19 from health.
Ozpinar et al. (Thu,) studied this question.