Study design and participants
In this retrospective study, we included 239 laboratory adult inpatients (≥ 18 years old) admitted at Wuhan Tongji Hospital (Wuhan, China) from February 9th, 2020 to March 9th, 2020 and who were diagnosed with COVID-19 according to to the Chinese management guideline for COVID-19 (version 7.0) and the World Health Organization interim guidance.
Severe and critically ill COVID-19 patients were identified by reviewing and analyzing admission logs and histories of all available electronic medical records and patient care resources independently by two physicians. The severe form of COVID-19 patients was defined as one or more of the following symptoms: 1. Shortness of breath, respiratory rate (RR) ≥ 30 breaths/minute; 2. PaO2/FiO2 ≤ 300mmHg; 3. SaO2 or SpO2 ≤ 93% on room air. A patient was considered to have progressed to critical illness if they experienced at least one of the following criteria: 1. Respiratory failure requiring mechanical ventilation; 2. Shock; 3. Combined organ failure requiring monitoring and treatment in intensive care unit (ICU). This study was approved by the Institutional Review Board at Wuhan Tongji Hospital (Wuhan, China) and The First Affiliated Hospital of Soochow University (Suzhou, China). As COVID-19 is classified as an emerging infectious disease, written informed patient consent was exempt.