Research in context
Evidence before this study
We searched PubMed with the terms “respiratory distress syndrome, adult” [MeSH terms] OR (“respiratory” [all fields] AND “distress” [all fields] AND “syndrome” [all fields] AND “adult” [all fields]) OR “adult respiratory distress syndrome” [all fields] OR (“acute” [all fields] AND “respiratory” [all fields] AND “distress” [all fields] AND “syndrome” [all fields]) OR “acute respiratory distress syndrome” [all fields]) AND “geographic” [all fields] OR “country” [all fields] for articles published in any language between Jan 1, 1990, and Dec 31, 2016, the date of our final search. We also reviewed the reference lists of publications identified by our search strategy. We found some studies of the epidemiology of acute respiratory distress syndrome (ARDS) within regions or small groups of countries (eg, Europe), but no data for ARDS across major geo-economic groupings. We also identified studies showing important geo-economic variations in diseases such as diabetes, asthma, chronic obstructive pulmonary disease, and myocardial infarction.
Added value of this study
Significant variations exist in demographics, risk factors for ARDS, and comorbid diseases across the three major geo-economic groupings included in our study—namely, high-income countries in Europe, high-income countries in the rest of the world, and middle-income countries. Severity of ARDS was less overall in high-income countries in the rest of the world than in high-income European or middle-income countries. In terms of patterns of care, use of prone positioning, neuromuscular blockade, and recruitment manoeuvres were more common in high-income European countries than in the other two geo-economic groups. Length of stay in intensive-care units was shorter, and unassisted ventilation to day 28 was more common, in high-income countries in the rest of the world than in high-income European or middle-income countries. Lower gross national product was associated with poorer hospital survival in patients with ARDS. Outcomes in middle-income countries were worse than those in either high-income country grouping.
Implications of all the available evidence
Important regional differences exist in the demographics, management, and outcomes of patients with ARDS. Our data show opportunities to increase implementation of evidence-based interventions that improve outcomes for patients.