key: cord-343940-fdnmeuh8
authors: Tzotzos, Susan J.; Fischer, Bernhard; Fischer, Hendrik; Zeitlinger, Markus
title: Incidence of ARDS and outcomes in hospitalized patients with COVID-19: a global literature survey
date: 2020-08-21
journal: Crit Care
DOI: 10.1186/s13054-020-03240-7
sha: 
doc_id: 343940
cord_uid: fdnmeuh8

nan

systems and to inform critical care clinicians. This information should enable the prediction of requirements for hospital resources and thereby facilitate planning an appropriate and timely response in the future.

We carried out regular searches of PubMed using combinations of the search terms "ARDS," "COVID-19," "clinical characteristics," "clinical features," "clinical findings," "ICU," "incidence," "outcome," and "prevalence" (last search July 31, 2020).

Over 1000 publications were retrieved from which only studies reporting consecutively hospitalized patients, and giving numbers for ARDS patients and outcomes, were selected. Meta-analyses were excluded.

Seventeen studies reporting results from 2486 hospitalized COVID-19 patients in five countries fitted the inclusion criteria (Tables 1 and 2 ). Limitations are that seven studies did not define ARDS and only one study classified patients as mild, moderate, and/or severe; the patient sample is comparatively small: twelve of the studies had less than 200 patients. Furthermore, there was heterogeneity in types of data gathered by each research group, hence for many of the studies, patient numbers did not permit calculation of all parameters (Tables 1 and 2) .

There is variability between individual studies with respect to frequency of ARDS, rates of ICU admission, and mortality among patients. Calculation of weighted averages for these parameters incorporating data from individual studies for which data is available indicate that among hospitalized COVID-19 patients, approximately 1/3 (33%) develop ARDS, 1/4 (26%) require transfer to Patient numbers for Chen T study not included an ICU, 1/6 (16%) receive IMV, and 1/6 (16%) die (Table 1 ). For COVID-19 patients transferred to an ICU, nearly 2/3 (63%) receive IMV and 3/4 (75%) have ARDS ( Table 2 ). The mortality rate of ICU COVID-19 patients is 40% and of those who receive IMV 59%; the mortality rate in COVID-19-associated ARDS is 45%, and the incidence of ARDS among non-survivors of COVID-19 is 90% ( Table 2 ). The high incidence of ARDS among COVID-19 patients revealed in our survey is consistent with the results of postmortem examinations of patients with COVID-19, in which the predominant finding is diffuse alveolar damage, the most frequent histopathologic correlate of ARDS. For as long as there is neither a safe and efficacious vaccine nor therapy for severely affected COVID-19 patients, standard supportive care with lung-protective mechanical ventilation will be the cornerstone of treatment for these patients [5, 6] . The implications of these survey results are important and demonstrate the considerable challenges posed by the "COVID-19 crisis" to ICU practitioners, hospital administrators, and health policy makers.

Susan 

Data generated or analyzed during this study are included in this published article.

Ethics approval and consent to participate Not applicable

All authors have approved the manuscript for submission. For study reference see Table 1 

Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: summary of a report of 72314 cases from the Chinese Center for Disease Control and Prevention

Mechanical ventilation in COVID-19: interpreting the current epidemiology

Risk factors associated with acute respiratory distress syndrome and death in patients with coronavirus disease 2019 pneumonia in Wuhan, China

Acute respiratory distress syndrome: the Berlin Definition

COVID-19-associated acute respiratory distress syndrome: is a different approach to management warranted?

Treatment for severe acute respiratory distress syndrome from COVID-19

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

Authors' contributions SJT conducted the literature search and survey. SJT, BF, and HF evaluated and contributed to the interpretation and presentation of the data. SJT drafted the manuscript; BF, HF, and MZ revised the final version of the manuscript. The authors read and approved the final manuscript. The authors declare that they have no competing interests.