Clinical characteristics and day-90 outcomes of 4244 critically ill adults with COVID-19: a prospective cohort study

Abstract

Purpose: To describe acute respiratory distress syndrome (ARDS) severity, ventilation management, and the outcomes of ICU patients with laboratory-confirmed COVID-19 and to determine risk factors of 90-day mortality post-ICU admission.

Methods: COVID-ICU is a multi-center, prospective cohort study conducted in 138 hospitals in France, Belgium, and Switzerland. Demographic, clinical, respiratory support, adjunctive interventions, ICU length-of-stay, and survival data were collected.

Results: From February 25 to May 4, 2020, 4643 patients (median [IQR] age 63 [54-71] years and SAPS II 37 [28-50]) were admitted in ICU, with day-90 post-ICU admission status available for 4244. On ICU admission, standard oxygen therapy, high-flow oxygen, and non-invasive ventilation were applied to 29%, 19%, and 6% patients, respectively. 2635 (63%) patients were intubated during the first 24 h whereas overall 3376 (80%) received invasive mechanical ventilation (MV) at one point during their ICU stay. Median (IQR) positive end-expiratory and plateau pressures were 12 (10-14) cmH₂O, and 24 (21-27) cmH₂O, respectively. The mechanical power transmitted by the MV to the lung was 26.5 (18.6-34.9) J/min. Paralyzing agents and prone position were applied to 88% and 70% of patients intubated at Day-1, respectively. Pulmonary embolism and ventilator-associated pneumonia were diagnosed in 207 (9%) and 1209 (58%) of these patients. On day 90, 1298/4244 (31%) patients had died. Among patients who received invasive or non-invasive ventilation on the day of ICU admission, day-90 mortality increased with the severity of ARDS at ICU admission (30%, 34%, and 50% for mild, moderate, and severe ARDS, respectively) and decreased from 42 to 25% over the study period. Early independent predictors of 90-day mortality were older age, immunosuppression, severe obesity, diabetes, higher renal and cardiovascular SOFA score components, lower PaO₂/FiO₂ ratio and a shorter time between first symptoms and ICU admission.

Conclusion: Among more than 4000 critically ill patients with COVID-19 admitted to our ICUs, 90-day mortality was 31% and decreased from 42 to 25% over the study period. Mortality was higher in older, diabetic, obese and severe ARDS patients.

Keywords: Acute respiratory distress syndrome; COVID-19; Mechanical ventilation; Mortality risk factor; Outcome.

Fig. 1

Flowchart of patients screening and inclusion. ICU intensive care unit

Fig. 2

Kaplan–Meier survival estimates during the 90 days following ICU admission, according to A) Acute Respiratory Distress Syndrome Severity in patients on invasive mechanical ventilation or non-invasive ventilation at Day-1; B) age categories; C) ARDS severity progression within 7 days in patients with mild ARDS at Day-1*; D) ARDS severity progression within 7 days in patients with moderate ARDS at Day-1. *Only patients alive at day-7 were included in this analysis. ICU intensive care unit