Biological Risk Factors Predict Transfer to Intensive Care Units and Death in Covid-19 Patients

Abstract

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), causing the COVID-19, has been declared as pandemic by the World Health Organization. Epidemiological and clinical characteristics of patients with COVID-19 have been largely reported but biological risk factors have not yet been well described. In this retrospective and monocentric study, we explored 35 hematological and biochemical parameters, routinely measured at the Amiens University Hospital laboratory, between February 21, 2020 and March 30, 2020 for patients diagnosed with COVID-19. 154 patients were included in this study. We compared biological parameters collected at hospital admission between patients who survived or not after hospitalization. Non survivor patients displayed lower hemoglobin (p=0.02) and bicarbonate concentrations (p=0.03) and higher potassium concentration (p=0.03) compared to the survivors. We then compared these biological parameters between patients hospitalized in conventional care units and patients hospitalized in intensive care units (ICU). Numerous biological examinations had significant variations, including lymphocyte and neutrophil counts, bicarbonate, calcium and C Reactive Protein concentrations. In multivariate Cox analysis, risk factors for aggravation (defined as ICU admission or death) included low bicarbonate levels and hyponatremia. A significant worse overall survival was associated with hyponatremia, hyperkaliemia and prothrombin time > 16.8 seconds. We then proposed a prognostic score, to be validated in a future prospective study. Thus, these biological parameters, easily available, could help clinicians to identify high risk patients at an early stage of infection.