Impact of low serum calcium at hospital admission on SARS-CoV-2 infection outcome

Background: Calcium is an essential ion for pathogen survival and virulence and is involved in the regulation of the inflammatory response. Hypocalcemia is a common laboratory finding in critically ill patients. Data regarding levels of calcium in SARS-CoV-2 infection is scarce. Patients with SARS-CoV-2 infection who present with hypocalcemia could have a worse outcome. Methods: We performed a retrospective analysis of hospitalized patients with SARS-CoV-2 infection and included all patients who had any serum calcium measurement in the first 72 h since hospital admission. The main objective was to investigate the relation of low serum calcium with adverse outcome, measured by the requirement of high oxygen support – defined as high flow nasal cannula oxygen, non-invasive mechanical ventilation and/or invasive ventilation – intensive care unit admission or death. Results: A total of 316 patients were included in the study. Median age was 65 years (IQR 55–74); 65% were men. Hypocalcemia within 72 h since hospital admission was present in 63% of patients. A higher number of patients in the hypocalcemia group required high oxygen support during hospitalization (49% vs 32%; p = 0,01) and were admitted to the ICU (42% vs 26%; p = 0,005). No differences in mortality were observed between groups. Conclusions: Hypocalcemia is frequent in hospitalized patients with SARS-CoV-2 infection and can identify patients who will have a worse outcome. More studies are needed to understand the role of calcium metabolism in SARS-CoV-2 infection and to address the clinical implications and therapeutic interventions it might have.