The Impact of Tocilizumab on Radiological Changes Assessed by Quantitative Chest CT in Severe COVID-19 Patients

(1) Background: We aimed to analyze the characteristics associated with the in-hospital mortality, describe the early CT changes expressed quantitatively after tocilizumab (TOC), and assess TOC timing according to the oxygen demands. (2) Methods: We retrospectively studied 101 adult patients with severe COVID-19, who received TOC and dexamethasone. The lung involvement was assessed quantitatively using native CT examination before and 7-10 days after TOC administration. (3) Results: The in-hospital mortality was 17.8%. Logistic regression analysis found that interstitial lesions above 50% were associated with death (p = 0.01). The other variables assessed were age (p = 0.1), the presence of comorbidities (p = 0.9), the oxygen flow rate at TOC administration (p = 0.2), FiO(2) (p = 0.4), lymphocyte count (p = 0.3), and D-dimers level (p = 0.2). Survivors had a statistically significant improvement at 7-10 days after TOC of interstitial (39.5 vs. 31.6%, p < 0.001), mixt (4.3 vs. 2.3%, p = 0.001) and consolidating (1.7 vs. 1.1%, p = 0.001) lesions. When TOC was administered at a FiO(2) <= 57.5% (oxygen flow rate <= 13 L/min), the associated mortality was significantly lower (4.3% vs. 29.1%, p < 0.05). (4) Conclusions: Quantitative imaging provides valuable information regarding the extent of lung damage which can be used to anticipate the in-hospital mortality. The timing of TOC administration is important and FiO(2) could be used as a clinical predictor.

Automated summary

This study aimed to analyze the factors associated with in-hospital mortality in severe COVID-19 patients, describe the quantitative CT changes after tocilizumab (TOC) administration, and evaluate the timing of TOC according to oxygen demands. The results showed that CT changes after TOC administration can predict in-hospital mortality, and the oxygen flow rate at TOC administration can be used as a clinical predictor.