Prompt predicting of early clinical deterioration of moderate-to-severe COVID-19 patients: usefulness of a combined score using IL-6 in a preliminary study

Vultaggio, Alessandra; Vivarelli, Emanuele; Virgili, Gianni; Lucenteforte, Ersilia; Bartoloni, Alessandro; Nozzoli, Carlo; Morettini, Alessandro; Berni, Andrea; Malandrino, Danilo; Rossi, Oliviero; Nencini, Francesca; Pieralli, Filippo; Peris, Adriano; Lagi, Filippo; Scocchera, Giulia; Spinicci, Michele; Trotta, Michele; Mazzetti, Marcello; Parronchi, Paola; Cosmi, Lorenzo; Liotta, Francesco; Fontanari, Paolo; Mazzoni, Alessio; Salvati, Lorenzo; Maggi, Enrico; Annunziato, Francesco; Almerigogna, Fabio; Matucci, Andrea

Abstract Background The early identification of patients at risk of clinical deterioration is of interest considering the timeline of COVID-19 after the onset of symptoms. Objective The aim of our study was to evaluate the usefulness of testing serum IL-6 and other serological and clinical biomarkers, to predict a short-term negative clinical course of non critical COVID-19 patients. Methods 208 patients with non critical COVID-19 pneumonia at admission were consecutively enrolled. Clinical and laboratory findings obtained upon admission were analyzed by using survival analysis and stepwise logistic regression for variable selection. Three-day worsening as outcome in a logistic model to generate a prognostic score was used. Results Clinical worsening occurred in 63 patients (16=died; 39=transferred to Intensive Care Unit; 8 worsening of respiratory failure). Forty-five of them worsened within 3 days after admission. The risk of clinical worsening was progressively enhanced along with increasing quartiles of IL-6 levels. Multivariate analysis showed that IL-6 (p=0.005), CRP (p=0.003) and SaO2/FiO2 (p=0.014) and were the best predictors for clinical deterioration in the first 3 days after admission. The combined score yielded an AUC=0.88 (95% CI 0.83–0.93). A nomogram predicting the probability of 3-day worsening was generated. The score also showed good performance for 7-day and 14-day or 21-day worsening and in predicting death occurring during all the follow-up. Conclusions Combining IL-6, CRP and SaO2/FiO2 in a score, may help clinicians to identify upon admission those patients with COVID-19 who are at high risk for a further 3-day clinical deterioration.