Abstract
Objective. Development and validation of a prognostic scale for mortality in patients with COVID-19-associated lung disease based on a new Composite Inflammatory-Thrombotic Index (CITI) and chest computed tomography (CT) data. Material and methods. Retrospective analysis of data from 95 patients with confirmed lung injury due to viral infection associated with COVID-19. The study assessed the visual lung lesion volume (in %) on CT, maximum D-dimer and interleukin-6 levels, and the minimum absolute lymphocyte count. The CITI index was calculated using the formula: (D-dimer × IL-6) / lymphocytes. This index combines three key pathophysiological components of severe systemic inflammation. D-dimer, as a marker of fibrinolysis and thrombus formation, which increases in thrombosis and disseminated intravascular coagulation (DIC), predicts death in sepsis and COVID-19 [1–3]. Interleukin-6 is a central cytokine of the «cytokine storm» and increases in hyperinflammation, endothelial damage, and ARDS [1–3]. Lymphopenia is an indicator of immunosuppression and an unfavorable prognostic outcome [3]. Based on these indicators, a standalone desktop application for physicians and clinicians was created to quickly calculate the CITI. CITI was compared with traditional inflammatory indices (NLR, SII), and ROC analysis and logistic regression were performed. Results. Mortality was recorded in 40 patients (47.3%). The median CITI in deaths was 1,240,000, compared to 68,000 in survivors
(р< 0.0001). The AUC for CITI was 0.98 (95% CI 0.95 — 1.00), exceeding the NLR (0.92) and SII (0.93). The combination of CITI > 500,000 and CT lung involvement > 70% was associated with a 95% mortality rate. Conclusion. The proposed CITI-based radiological laboratory scale has high prognostic accuracy and can be used for early stratification of the risk of death in patients with COVID-19-associated lung disease.