Epidemiological characteristics, clinical features and outcomes of patients with COVID-19 admitted to seven reference centers across Greece: An observational study during the fourth and fifth waves of the COVID-19 pandemic

INTRODUCTION Epidemiological data from hospitalized patients with COVID-19 during the fourth and fifth waves of the pandemic have been published worldwide.METHODS This registry was an observational, prospective study conducted in seven reference hospitals across Greece. Maximum FiO2 during hospitalization and Charlson comorbidity index (CCI) on admission were correlated with disease severity, as well as radiological features, parameters of complete blood count, and d-dimer.RESULTS A total of 1019 patients were included in the analysis; 55.1% and 57.2% of patients were males and never smokers, respectively, with median age of 67 years (95% CI: 65.7-69.0). Patients with increased extent of consolidation and ground glass opacities in chest CT (>10-25%) exhibited more advanced disease compared to the low extent group (<10%) as indicated by both CCI on admission (3; 95% CI: 2-3 vs 2; 95% CI: 1-2, p=0.0002) and MaxFiO2 (0.40; 95% CI: 0.35-0.40 vs 0.28; 95% CI: 0.24-0.28, p<0.0001). Patients with high neutrophil to lymphocyte ratio (>_4.42) exhibited more severe disease as indicated by significantly increased CCI on admission (4; 95% CI: 3 to 4 vs 3; 95% CI: 2-3, p<0.0001) and MaxFiO2 (0.35; 95% CI: 0.35-0.4 vs 0.28; 95% CI: 0.28-0.28, p<0.0001). Patients with elevated d-dimer (>_0.74 & mu;g/mL) displayed also advanced disease compared to the low d-dimer group (<0.74 & mu;g/mL), as assessed by both CCI on admission (4; 95% CI: 4-4 vs 2; 95% CI: 2-2, p<0.0001) and MaxFiO2 (0.38; 95% CI: 0.35-0.40 vs 0.28; 95% CI: 0.28-0.28, p<0.0001).CONCLUSIONS We present the first observational study across Greece during the fourth and fifth waves of the COVID-19 pandemic. Extent of opacities in chest CT, neutrophil to lymphocyte ratio and d-dimer may represent reliable disease prognostic factors leading to timely therapeutic interventions.