Patient characteristics
The COVID-19 patients were administered an approved questionnaire upon
enrolment to collect information regarding COVID-19-related symptoms
prior to hospitalization and smoking behaviours. The date of COVID-19
diagnosis, highest level of care received, the maximum amount of oxygen
supplementation required (unit, oxygen need 5L/min supplemented by High
Flow Nasal Oxygen (HFNO) or Continuous Positive Airway Pressure (CPAP)),
and the critical care provided (intensive care unit, with or without
mechanical ventilation) for COVID-19 illness were all gathered from
digital medical records.