Clinical characteristics, risk factors and outcomes in patients with severe COVID-19 registered in the International Severe Acute Respiratory and Emerging Infection Consortium WHO clinical characterisation protocol: a prospective, multinational, multicentre, observational study

Abstract

Due to the large number of patients with severe coronavirus disease 2019 (COVID-19), many were treated outside the traditional walls of the intensive care unit (ICU), and in many cases, by personnel who were not trained in critical care. The clinical characteristics and the relative impact of caring for severe COVID-19 patients outside the ICU is unknown. This was a multinational, multicentre, prospective cohort study embedded in the International Severe Acute Respiratory and Emerging Infection Consortium World Health Organization COVID-19 platform. Severe COVID-19 patients were identified as those admitted to an ICU and/or those treated with one of the following treatments: invasive or noninvasive mechanical ventilation, high-flow nasal cannula, inotropes or vasopressors. A logistic generalised additive model was used to compare clinical outcomes among patients admitted or not to the ICU. A total of 40 440 patients from 43 countries and six continents were included in this analysis. Severe COVID-19 patients were frequently male (62.9%), older adults (median (interquartile range (IQR), 67 (55-78) years), and with at least one comorbidity (63.2%). The overall median (IQR) length of hospital stay was 10 (5-19) days and was longer in patients admitted to an ICU than in those who were cared for outside the ICU (12 (6-23) days versus 8 (4-15) days, p<0.0001). The 28-day fatality ratio was lower in ICU-admitted patients (30.7% (5797 out of 18 831) versus 39.0% (7532 out of 19 295), p<0.0001). Patients admitted to an ICU had a significantly lower probability of death than those who were not (adjusted OR 0.70, 95% CI 0.65-0.75; p<0.0001). Patients with severe COVID-19 admitted to an ICU had significantly lower 28-day fatality ratio than those cared for outside an ICU.

FIGURE 1

Study flow chart. ISARIC: International Severe Acute Respiratory and Emerging Infection Consortium; WHO: World Health Organization; COVID-19: coronavirus disease 2019; ICU: intensive care unit.

FIGURE 2

Patients with severe coronavirus disease 2019 were enrolled in six continents. The colour scale shows the number of patients included in each country. Grey shading represents countries with no patients included in this analysis.

FIGURE 3

Patients admitted to the intensive care unit (ICU) have lower cumulative deaths over time. a) The cumulative number of cases included in the study, stratified by b) patients admitted to the ICU and c) patients who were not admitted to the ICU. Proportions of patients still hospitalised at the moment of data extraction, discharged alive and reported dead are shown.

FIGURE 4

Estimation of the non-linear effect on 28-day fatality ratio using a generalised additive model in patients with severe coronavirus disease 2019 (COVID-19) stratified by intensive care unit (ICU) admission. a) Age is shown to be an essential factor for higher fatality ratio in patients with severe COVID-19; however, patients admitted to the ICU have a lower fatality ratio independent of age. Even after adjusting by b) the number of new cases per million at the moment of hospital admission and c) the interaction over time, the marginal 28-day fatality ratio was lower in patients admitted to the ICU.