J Clin Med

. 2021 Jan 15;10(2):E305.
doi: 10.3390/jcm10020305.
The Prognostic Value of Eosinophil Recovery in COVID-19: A Multicentre, Retrospective Cohort Study on Patients Hospitalised in Spanish Hospitals

María Mateos González 1 , Elena Sierra Gonzalo 2 , Irene Casado Lopez 1 , Francisco Arnalich Fernández 3 , José Luis Beato Pérez 4 , Daniel Monge Monge 5 , Juan Antonio Vargas Núñez 6 , Rosa García Fenoll 7 , Carmen Suárez Fernández 8 , Santiago Jesús Freire Castro 9 , Manuel Mendez Bailon 10 , Isabel Perales Fraile 11 , Manuel Madrazo 12 , Paula Maria Pesqueira Fontan 13 , Jeffrey Oskar Magallanes Gamboa 14 , Andrés González García 15 , Anxela Crestelo Vieitez 16 , Eva María Fonseca Aizpuru 17 , Asier Aranguren Arostegui 18 , Ainara Coduras Erdozain 19 , Carmen Martinez Cilleros 20 , Jose Loureiro Amigo 21 , Francisco Epelde 22 , Carlos Lumbreras Bermejo 23 , Juan Miguel Antón Santos 1 , For The Semi-Covid-Network



Objectives: A decrease in blood cell counts, especially lymphocytes and eosinophils, has been described in patients with serious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), but there is no knowledge of their potential role of the recovery in these patients' prognosis. This article aims to analyse the effect of blood cell depletion and blood cell recovery on mortality due to COVID-19.
Design: This work was a retrospective, multicentre cohort study of 9644 hospitalised patients with confirmed COVID-19 from the Spanish Society of Internal Medicine's SEMI-COVID-19 Registry.
Setting: This study examined patients hospitalised in 147 hospitals throughout Spain.
Participants: This work analysed 9644 patients (57.12% male) out of a cohort of 12,826 patients ≥18 years of age hospitalised with COVID-19 in Spain included in the SEMI-COVID-19 Registry as of 29 May 2020.
Main outcome measures: The main outcome measure of this work is the effect of blood cell depletion and blood cell recovery on mortality due to COVID-19. Univariate analysis was performed to determine possible predictors of death, and then multivariate analysis was carried out to control for potential confounders.
Results: An increase in the eosinophil count on the seventh day of hospitalisation was associated with a better prognosis, including lower mortality rates (5.2% vs. 22.6% in non-recoverers, OR 0.234; 95% CI, 0.154 to 0.354) and lower complication rates, especially regarding the development of acute respiratory distress syndrome (8% vs. 20.1%, p = 0.000) and ICU admission (5.4% vs. 10.8%, p = 0.000). Lymphocyte recovery was found to have no effect on prognosis. Treatment with inhaled or systemic glucocorticoids was not found to be a confounding factor.
Conclusion: Eosinophil recovery in patients with COVID-19 who required hospitalisation had an independent prognostic value for all-cause mortality and a milder course.

Keywords: 2019-nCoV; COVID-19; SARS-CoV-2; coronavirus; eosinophil; prognosis.