The severity of COVID-19 disease ranges from asymptomatic to severe, life-threatening symptoms. The aim of our study was to co-evaluate magnesium and 25-hydroxyvitamin D₃ in predicting the severity of this disease.

This study included 232 inpatients with COVID-19 and 250 healthy individuals (control group). Magnesium and 25-hydroxyvitamin D₃ levels were compared. ROC curve analysis was performed by co-evaluation of magnesium and 25-hydroxyvitamin D₃ levels. Correlation analysis was performed between co-evaluation of magnesium and 25-hydroxyvitamin D3 levels together and the laboratory parameters used in the prognosis of COVID-19 disease.

Magnesium and 25-hydroxyvitamin D₃ levels of the group with COVID-19 were lower than the control group (p< 0.001). AUC value was found to be 0.924 in ROC curve analysis (p< 0.001). In the ROC curve analysis, the cut-off value for magnesium was found to be 2.20, and the cut-off value for 25-hydroxyvitamin D₃ was found as 25.80. Co-evaluation of magnesium and 25-hydroxyvitamin D₃ levels were negatively correlated with D-dimer, C reactive protein, procalcitonin, neutrophil lymphocyte ratio and monocyte lymphocyte ratio (P< 0.05).

Co-evaluation of magnesium and 25-hydroxyvitamin D₃ may be useful in predicting the severity of the disease in patients with COVID-19. Low magnesium and 25-hydroxyvitamin D₃ levels can be considered a risk factor in patients with COVID-19. People with magnesium and 25-hydroxyvitamin D₃ deficiencies may be considered at risk for COVID-19 disease. We recommend monitoring of magnesium and 25-hydroxyvitamin D₃ levels to predict the prognosis of the COVID-19 disease. Individuals may be offered prophylactic magnesium and 25-hydroxyvitamin D₃ supplementation.