Epidemiological, clinical and laboratory profile of Covid patients during third wave in a tertiary care ICU setup in New Delhi

Background: The world has seen multiple peaks and troughs due to various strains of SARS-CoV-2 virus since December 2019. We present the epidemiology, clinical and laboratory profile of critically ill patients infected with omicron strain during the third wave in a tertiary care ICU setup in New Delhi. Methods: This was a prospective observational study, including all positive patients admitted to a tertiary care COVID ICU from 20th December 2021 to 28th February 2022. All demographic, clinical and laboratory data of patients was recorded from their medical records without revealing their identity. The patients were then followed up to document the treatment received in ICU, eventual outcome and length of ICU stay. Results: A total of 112 patients were included in the study, out of which 54.5% of the patients succumbed to the infection. More than half the patients (56.3%) did not present with respiratory involvement, suggesting either a change in symptomatology from previous waves, or incidental COVID infections in otherwise ill patients. Upon further analysis, it was found that male sex, increasing age, higher Neutrophil-Lymphocyte Ratio (NLR) and C-Reactive Protein (CRP) on admission, lower PaO2/FiO2 Ratio (PF Ratio) and requirement of high-grade antibiotics had a positive correlation with patient mortality. ROC analysis revealed that optimal cut-offs for CRP, NLR and D-dimer for predicting mortality were 87.5 mg/l, 6.57 and 408.50 ng/ml, respectively. Conclusion: The above results indicate that omicron strain presents with more extra-pulmonary symptoms or incidental infections in already hospitalized patients than previous strains. Elderly males, severe pulmonary involvement, high NLR ratio and CRP on admission and requirement of higher antibiotics in ICU affect patient outcome.