Articles
Geo-economic variations in epidemiology, patterns of care, and outcomes in patients with acute respiratory distress syndrome: insights from the LUNG SAFE prospective cohort study

https://doi.org/10.1016/S2213-2600(17)30213-8Get rights and content

Summary

Background

Little information is available about the geo-economic variations in demographics, management, and outcomes of patients with acute respiratory distress syndrome (ARDS). We aimed to characterise the effect of these geo-economic variations in patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE).

Methods

LUNG SAFE was done during 4 consecutive weeks in winter, 2014, in a convenience sample of 459 intensive-care units in 50 countries across six continents. Inclusion criteria were admission to a participating intensive-care unit (including transfers) within the enrolment window and receipt of invasive or non-invasive ventilation. One of the trial's secondary aims was to characterise variations in the demographics, management, and outcome of patients with ARDS. We used the 2016 World Bank countries classification to define three major geo-economic groupings, namely European high-income countries (Europe-High), high-income countries in the rest of the world (rWORLD-High), and middle-income countries (Middle). We compared patient outcomes across these three groupings. LUNG SAFE is registered with ClinicalTrials.gov, number NCT02010073.

Findings

Of the 2813 patients enrolled in LUNG SAFE who fulfilled ARDS criteria on day 1 or 2, 1521 (54%) were recruited from Europe-High, 746 (27%) from rWORLD-High, and 546 (19%) from Middle countries. We noted significant geographical variations in demographics, risk factors for ARDS, and comorbid diseases. The proportion of patients with severe ARDS or with ratios of the partial pressure of arterial oxygen (PaO2) to the fractional concentration of oxygen in inspired air (FiO2) less than 150 was significantly lower in rWORLD-High countries than in the two other regions. Use of prone positioning and neuromuscular blockade was significantly more common in Europe-High countries than in the other two regions. Adjusted duration of invasive mechanical ventilation and length of stay in the intensive-care unit were significantly shorter in patients in rWORLD-High countries than in Europe-High or Middle countries. High gross national income per person was associated with increased survival in ARDS; hospital survival was significantly lower in Middle countries than in Europe-High or rWORLD-High countries.

Interpretation

Important geo-economic differences exist in the severity, clinician recognition, and management of ARDS, and in patients' outcomes. Income per person and outcomes in ARDS are independently associated.

Funding

European Society of Intensive Care Medicine, St Michael's Hospital, University of Milan-Bicocca.

Introduction

Important geographical and economic variations in epidemiology and patterns of care have been described for diseases including diabetes,1 asthma,2 myocardial infarction,3, 4 heart failure,5 atrial fibrillation,6 chronic obstructive pulmonary disease (COPD),7 end-stage kidney disease,8 and breast cancer.9 Furthermore, use of interventions such as blood transfusion,10 amputation,11 aneurysm repair,12 and carotid revascularisation13—and outcomes after interventions such as coronary artery bypass grafting14—also vary by region or socioeconomic status, or both. Thus, geo-economic variations in the epidemiology and management of patients with acute respiratory distress syndrome (ARDS) could have important effects on patient outcomes, but the extent and implications of these variations have not been characterised.

The Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE)15 in 459 intensive-care units (ICUs) in 50 countries on six continents showed a two-fold variation in the incidence of ARDS per ICU bed across the continents, which was independent of clinician recognition. ARDS was under-recognised by clinicians, and the use of evidence-based ventilatory strategies and adjuncts was less common than expected. Of most concern, ARDS had high mortality, with 40% of patients dying in hospital.15

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.

A key secondary aim of LUNG SAFE was to characterise geo-economic variations in demographics, management, and outcomes of patients with ARDS. We compared patients across three major geo-economic groupings.

Section snippets

Study design and participants

Detailed methods for LUNG SAFE have been published elsewhere.15 Briefly, LUNG SAFE was an international, multicentre, prospective cohort study, with a 4-week enrolment window during the winter in each hemisphere.15 The study, which was conceived by the Acute Respiratory Failure Section of the European Society of Intensive Care Medicine, was endorsed by several national societies and networks (appendix). Its primary outcomes were to determine the incidence of ARDS in ICUs, and management of ARDS

Results

Of the 12 906 patients screened for the LUNG SAFE study, 2813 (22%) fulfilled ARDS criteria on day 1 or 2 after enrolment. Of these 2813 participants, 1521 (54%) were recruited from Europe-High, 746 (27%) from rWORLD-High, and 546 (19%) from Middle countries (figure 1). In Europe-High countries, 23% of screened patients had ARDS, compared with 21% in both rWORLD-High and Middle countries (table 1). Overall 300 (65%) of the 459 participating ICUs were in academic hospitals, with a median of 14

Discussion

In this prospective observational cohort study, we noted important differences in severity patterns, extent of clinician recognition, and approaches to management of ARDS across geo-economic regions. Patients from Europe-High countries had longer durations of mechanical ventilation and ICU stays than did patients from rWORLD-High countries. We show for the first time (to our knowledge) that indices of national socioeconomic status are associated with survival in ARDS.

Although the patients from

References (35)

  • Global report on diabetes

    (2016)
  • JM Chamberlain et al.

    Practice pattern variation in the care of children with acute asthma

    Acad Emerg Med

    (2016)
  • JM Brooks et al.

    Geographic variation in statin use for complex acute myocardial infarction patients: evidence of effective care?

    Med Care

    (2014)
  • ES Spatz et al.

    Geographic variation in trends and disparities in acute myocardial infarction hospitalization and mortality by income levels, 1999–2013

    JAMA Cardiol

    (2016)
  • J Oldgren et al.

    Variations in cause and management of atrial fibrillation in a prospective registry of 15 400 emergency department patients in 46 countries: the RE-LY Atrial Fibrillation Registry

    Circulation

    (2014)
  • P Yin et al.

    Spatiotemporal variations in chronic obstructive pulmonary disease mortality in China: multilevel evidence from 2006 to 2012

    COPD

    (2016)
  • MR Patel et al.

    Geographic variation in carotid revascularization among Medicare beneficiaries, 2003–2006

    Arch Intern Med

    (2010)
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