The aim of the work was to conduct a retrospective analysis of the clinical data of patients with pneumonia caused by the SARS-CoV-2 virus, and to determine via mathematical methods the significance of some physiological and biochemical indices as predictive markers of an unfavorable outcome of the disease. A random cohort of patients with COVID-19 pneumonia numbered 209 people. Mathematical analysis addressed the physiological characteristics of patients recorded at the time of hospital admission, as well as blood coagulation parameters and those reflecting the development of an inflammatory reaction. The analyzed parameters were categorized relative to the reference ranges of physiologically normal values. Correlation analysis was carried out using categorical data on the disease outcome. The algorithms for calculating statistical characteristics, as well as results visualization, were programmed in Python. When comparing patient groups, the significance of differences between the determined parameters was assessed using the Pearson's χ2 test with Yates' correction. The study showed that the age over 50 and male sex can be considered risk factors for patients with COVID-19 pneumonia (p < 0.05). The disease outcome was found to be significantly affected by cardiovascular pathologies (p < 0.01) and to a lesser extent by diabetes mellitus (p < 0.10). There were revealed maximal correlation coefficients between the oxygen saturation level (-0.43), as well as the breathing rate (0.43), and a fatal outcome of the disease. For patients over 50 years of age, oxygen saturation below 80% at the time of hospital admission turned out to be a marker of mortality. It was shown that D-dimer blood levels above 625 ng/mL in patients over 80 years of age correlated with mortal outcomes. No correlation was found between the C-reactive protein (CRP) level and the disease outcome. The effect of corticosteroids on the disease outcome was analyzed in patients with different CRP levels. It was found that, while using corticosteroids, the mortality rate in patients with CRP ≤ 12.5 mg/L is 2.7 times higher than in those with CRP > 12.5 mg/L (p < 0.01). Thus, the use of adequate mathematical methods made it possible to define more precisely some mortality-associated physiological and biochemical indices in patients with COVID-19 pneumonia.
Keywords: COVID-19; mathematical analysis; physiological and biochemical indices; pneumonia; retrospective data.
© Pleiades Publishing, Ltd. 2021.