Mathematical Analysis of the Accuracy of the Evaluation Criterion X in Patients with COVID-19 Infection

Abstract

Prognostic criterion X is calculated using an equation that includes 7 indexed parameters (age and body temperature of the patient, oxygen saturation (SatO?), number of blood neutrophils, values of creatinine, C-reactive protein and blood creatinine). Criterion X is measured in points, the number of which is directly proportional to the severity of the disease. The accuracy of criterion X was estimated by the method of ordinary least squares regression (OLS regression) and correlation analysis according to the criteria of r Pearson and rs Spearman in 305 patients with COVID-19 infection and pneumonia. The data obtained were compared by assessing the severity of the disease according to the general clinical parameters Xcl (state of consciousness, body T °C, pulse and respiratory rate per minute) and the NEWS-2 criterion. The results of the OLS regression demonstrate that there is a strong linear relationship between Xcl and X (Xev) (linear regression coefficient β1 = 0.8057, the standard deviation (std) of the coefficient β1 is s1 = 0.022). The coefficient of determination of this regression is R2 = 0.821. This means that the assessment of the severity of the disease and its prognosis for Xcl and X coincide with each other in 82% of cases. A comparison of the criteria X (Xev) and XNEWS-2 indicates the absence of a linear relationship between them (the value of the linear regression coefficient β1= 0.0553. The std of the coefficient β1 is s1 = 0.002). The comparison of the Xcl and XNEWS-2 criteria was not carried out due to the lack of data in the public domain. The evaluation criterion X meets the necessary statistical requirements and can be used to objectively assess the severity of inflammatory diseases, as well as to develop treatment regimens.