Comparative analysis of risk factors for death in patients of different age groups with severe COVID-19-associated pneumonia

The study examines the risk factors for mortality in patients across various age groups through a retrospective analysis of 591 medical records of patients with severe COVID-19-associated pneumonia treated in the intensive care unit (ICU). Univariate and multivariate analyses were conducted to identify risk factors for mortality in two distinct groups: patients under the age of 60 (group 1) and those aged 60 years and older (group 2), and comparative analysis between these two groups was performed. Mortality in group 1 was observed to be 46.9%, whereas in group 2 it was 73.3%. Patients in group 2 exhibited a comparatively lower weight and body mass index (BMI), a higher number of concomitant diseases, and more severe assessments according to the APACHE II and SOFA scales. The clinical presentation on day 1 did not differ between the groups based on the following criteria: hypercoagulation (93.1% in group 1 and 93.3% in group 2, p=0.950), septic shock (11.9% in group 1 and 18.1% in group 2, p=0.080), acute kidney injury (AKI) (12.5% in group 1 and 16.7% in group 2, p=0.206), and multiple organ failure syndrome (MODS) (55% in group 1 and 52.2% in group 2, p=0.236). In group 1, a higher prevalence of acute liver failure was observed (25% vs. 5.1%, p<0.001), whereas group 2 exhibited a greater incidence of acute cerebral failure (ACF) (13.8% vs. 34.8%, p=0.001). Group 1 also demonstrated significantly elevated leukocytosis (p<0.001) and alanine aminotransferase (ALT) levels (p<0.001). Conversely, group 2 showed lower levels of lymphopenia (p<0.001), hypoalbuminemia (p<0.001), and platelet count (p<0.001), in addition to higher levels of blood urea nitrogen (p<0.001), creatinine (p<0.001), and brain natriuretic hormone (NTproBNP) (p=0.003). In patients under 60 years old with severe COVID-19-associated pneumonia, the independent risk factor for death was the development of MODS on the first day of admission in the ICU. For patients over 60 years old, independent risk factors for death were age, the presence of chronic kidney disease (CKD), the severity of hypoxia as determined by the PaO2/FiO2 ratio upon admission to the ICU, the development of MODS, septic shock, and acute cerebral disorder. Keywords: coronavirus disease 2019, COVID-19, predictors, age, risk factors