(322) Operationalizing the New Global Definition of ARDS: An Epidemiological Report From South Africa

Introduction: The Berlin Definition of ARDS has received critique for missing patients in resource-variable settings and those treated with non-invasive respiratory support modalities including many with COVID-19. We sought to operationalize the new proposed Global Definition of ARDS and report updated ARDS epidemiology in a resource-limited setting.

Methods: The SA-ICU-Strain Study Group performed a retrospective cohort study in two public hospitals in the KwaZulu-Natal Department of Health, South Africa, January 2017 – June 2022, among adult patients meeting criteria for Berlin Definition ARDS or the New Global Definition of ARDS at ICU admission.

Results: Among 6,265 ICU admissions, 2,029 (32.4%) patients met at least one ARDS definition: 1,220 (19%) Berlin Definition, 1,349 (22%) Global Definition Intubated, 381 (6%) Global Definition Non-Intubated, and 2,029 (32%) Global Definition Resource-Limited Settings Modification. 809 new diagnoses of ARDS were made that were not captured by the Berlin Definition alone (12.9% of all ICU admissions; 39.9% of all ARDS diagnoses). After adjustment for hospital-level factors, patients who met Global Definition–only ARDS criteria had no statistically significant ICU mortality difference versus patients with Berlin Definition ARDS (21.6% [95% confidence interval (CI) 18.9-24.4%] vs 23.8% [95% CI 21.4-26.2%], odds ratio 0.88 [95% CI 0.71-1.10, p = 0.25]). In pre-specified exploratory subgroup analyses of the Global Definition–only ARDS cohort, a signal towards decreased ICU mortality was found in patients with trauma or non-infection/non-trauma primary ICU admission diagnoses, surgical referrals, patients with HIV infection, and in non–COVID-19 patients. In contrast, a signal towards increased ICU mortality was found in patients with COVID-19. In the Global Definition–only ARDS cohort, ICU mortality narrowed between mild and moderate severity and worsened in the severe severity classifications.

Conclusions: The New Global Definition of ARDS captures a significant proportion of patients who would not have been included by the Berlin Definition alone. These additional ARDS patients may have heterogenous patterns of outcomes between diagnostic subgroups, including COVID-19, and across oxygenation severity classifications compared to Berlin Definition ARDS patients.