Predictors of a severe course and mortality in patients with COVID-19–associated pneumonia
Authors: Blagoeva Vesela , Hodzhev Vladimir , Dimova Rositsa , Stoyanova Rumyana , Bahariev Dimitar 
Published: February 2024

Introduction: Severe and critical forms of SARS-CoV-2 pneumonia are associated with high morbidity and mortality. Numerous research studies have been conducted around the world to investigate various variables (demographic, clinical, laboratory, etc.) in an attempt to understand the relationships between them and the course and outcome of patients with COVID-19 infection and pneumonia.
Aim: To outline predictors of a severe or critical course and fatal outcome in patients with COVID-19–associated pneumonia.
Materials and methods: The current study was conducted from August 2021 to April 2022 in the COVID-19 ward of the Clinics of Pulmonology and Phthisiology at St George University Hospital in Plovdiv. It included 146 patients with PCR-confirmed COVID-19 and with anamnestic, laboratory, and imaging evidence of pneumonia. The patients were divided into three groups based on the severity of infection: moderate, severe, and critical. Demographic, clinical, laboratory, and imaging studies were performed for all patients. The data was exported to IBM SPSS v. 23 statistical software and analyzed with descriptive statistics, parametric and non-parametric methods. The relationships between the above-mentioned indicators and the severe or critical course and fatal outcome of the COVID-19 infection were outlined. A regression model was applied if the tested variables had a statistically significant correlation with the lethal outcomes.
Results: The age and sex of the patients appeared to be the most important demographic factors: the mean age of the patients who were discharged was 57 years, whereas the mean age of the deceased patients was 71 years. However, there was no statistically significant difference between the mortality rates of the age group under 65 and the age group over 65. Regarding sex, 30.8% of men and 25.5% of women had a fatal outcome, the difference failing to reach statistical significance (p=0.159). Among the clinical signs at admission, shortness of breath and mental status changes were related to a more severe course of the disease and increased mortality: statistically significant difference was found depending on the absence or presence of dyspnea (p=0.039). Of the patients without dyspnea, 90.9% were discharged, unlike 79.1% of the patients who had it, which makes a mortality rate of 29% for the latter group. There was also a statistically significant difference in the outcome depending on the presence of mental status changes – 45.5% of patients without mental status changes were discharged, whereas only 12% of those with mental status changes were discharged (p=0.011). Elevated D-dimers also seemed to affect the outcome – 82.2% of deceased patients had D-dimer levels of &gt;0.5. In terms of illness severity, the disease had a moderate course in 46 (65.2%) patients without raised D-dimers, and a severe course in 75 (72.2%) patients who had elevated D-dimer levels, and a critical course in 22 (76%) patients. There was a statistically significant difference between the pO2 values and disease severity – the probability of a severe and critical course in those with pO2&lt;60 mmHg was 77.2% (p=0.002). Presence of alveolar infiltrates seen in chest x-ray (CXR) or CT studies also led to a severe or critical course (p=0.000). The regression model showed that the three independent variables, shortness of breath, confusion at admission, and pO2 level &lt;60, were found to be statistically significant based on the Wald criterion (p&lt;0.000).
Conclusions: The results of the study indicated that older age, shortness of breath, and altered mental state at admission are predictors of severe or critical course and lethal outcome in patients with COVID-19 pneumonia. Regarding the laboratory tests, the elevated D-dimers and pO2 levels &lt;60 also indicate high risk and lethal outcomes.