Phenotyping COVID-19 inpatients prognosis at admission based upon serum biomarkers: a retrospective monocentric study

ABSTRACT

Background: Prompt recognition of COVID-19 prognosis could improve the care of inpatients admitted to Internal Medicine wards. Aim. To evaluate the impact of serum biomarkers at admission on COVID-19 prognosis. Methods: Two hundred eighteen COVID-19 patients referred to the Internal Medicine Baccelli, University of Bari were consecutively analyzed (September 2020 - June 2021) in a retrospective, monocentric study. A complete medical history, physical examination, blood count, renal function, inflammatory biomarkers, and total serum calcium were obtained. Results: Low serum calcium was found on average (8.4 mg/dl) but it normalized after correction for albuminemia (8.9 mg/dL). Patients transferred to the intensive care unit showed a statistically significant lower serum calcium (8.1 vs 8.4 mg/dL, p<0.01) compared to those not transferred to the intensive care even if relation vanished after albumin correction. Older age (81 vs 63y, p <0.001), higher C reactive protein (114 vs 38.5 mg/dL, p <0.001), d-dimer (2543 vs 641 ng/mL, p <0.001), lactic dehydrogenase (301 vs 236 UI/L, p <0.001), neutrophil-to-lymphocyte ratio (9.9 vs 4.5, p <0.001), interleukin- 6 (118 vs 21.6 pg/mL, p <0.001), creatinine (1.17 vs 0.88 mg/dL, p <0.001), and corrected calcium (9.2 vs 8.4 mg/dL, p<0.001) predicted death. Conclusions: Low total serum calcium might anticipate patients' transfer to the intensive care unit. This phenomenon may be driven by hypoalbuminemia. Advanced age, higher inflammatory biomarkers and creatinine, and higher serum calcium corrected for albumin may predict death.