Hypocalcemia as a Risk of COVID-19 Mortality: What Level of Hypocalcemia? Direct Measurement or Corrected Calcium Value?

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Aim: The negative effects of vitamin D deficiency and hypocalcemia on the frequency and severity of COVID-19 are quite striking. To determine the presence of hypocalcemia in hospitalized COVID-19 patients, the relationship between severity and outcome, and whether albumin correction is necessary to predict this relationship. Materials and methods: Hospitalized COVID-19 patients were grouped for lung involvement, need for intensive care, need for mechanical ventilation, long hospitalization (≥14 days), sepsis, and mortality. Blood calcium, albumin, 25OHvitamin D, parathyroid hormone, phosphorus, and magnesium values and albumin-corrected calcium data were evaluated retrospectively. Results: The study included 129 hospitalized COVID-19 patients, 67 (51.9%) male and 62 (40%) female. Vitamin D was insufficient in 89.9% of the patients and no association was found with disease severity. Calcium levels were significantly lower in terms of need for intensive care, sepsis, mechanical ventilation and mortality (p: 0.00, 0.013, 0.021, 0.004, respectively). No association was found with corrected Ca (p>0.05 for all). A significant increase was found in the same cases when total Ca values were below 8 mg/dl (p: 0.00, 0.001, 0.005 and 0.001, respectively). In the logistic regression analysis, it was found that age, increase in CRP and decrease in Ca levels significantly increased the risk for mortality (p: 0.005, 0.001 and 0.013, respectively). Conclusion: We found that total Ca values obtained by direct measurement below 8 mg/dl in COVID-19 patients are significantly more likely to require intensive care, require mechanical ventilation, sepsis and mortality, and in the analysis we determined that age, CRP and a decrease in direct measured total Ca values, together with advanced age and high CRP, are risk factors that increase mortality.