The International Epidemiology of Acute Respiratory Distress Syndrome: How Can We Think Locally and Measure Globally?* MajidAfshar, MD, MSCR Division of Pulmonary and Critical Care Medicine University of Maryland Baltimore, MD
study enrolled 773 patients at multiple centers from the Brazilian Research in Intensive Care Network (BRICNet) across 12 states and found that ARDS developed in one third of patients requiring mechanical ventilation (8). In the current study. Caser et al (7) performed a population-based cohort Giora Netzer, MD, MSCE study over a 15-month period in 14 ICUs and screened 7,133 Division of Pulmonary and Critical Care Medicine; and patients for acute lung injury by AECC definition and ARDS Department of Epidemiology and Public Health by Berlin Definition. They reported a lower prevalence than University of Maryland the population-based cohort studies from United States. SevBaltimore, MD eral possibilities exist to explain this disparity. The ARDS definitions differ; they added 24 hours of mechanical ventilation to their definition for ARDS. The population differs he first syndromic definition of the acute respiraas well; patients with known risk factors for ARDS, includtory distress syndrome (ARDS) (1) was created by ing chronic liver disease, chronic renal failure, and chronic Americans to recognize a serious condition with high obstructive pulmonary disease, were excluded from analysis. mortality. The subsequent American European Consensus Conference (AECC) provided a uniform definition for the The source and vahdity of the population-based denominator is also unclear. syndrome (2), facilitating paradigm-shifting clinical trials performed by ARDS Network (ARDSNet), funded by the National This study shows that the Brazilian critical care commuHeart, Lung and Blood Institute (3). The consensus definition nity, in addition to being well organized (with two critical also facilitated rigorous population-based studies estimating care societies and its BRICNet), has and will continue to the prevalence of ARDS in the United States (4, 5). make important contributions to our understanding of lung More recently, the ARDS Definition Task Force refined the injury. This study also makes clear that rigorous epidemiosyndrome with the Berlin Definition, providing variables on logic assessment of ARDS is an international impetus, and acuity, requirements for mechanical ventilation, and stratificaour consideration of ARDS must extend past traditional tion of ARDS severity (6). The Berlin Definition came from borders. In assessing future studies from country to counan international consensus of researchers from industrialized try, we may need to reconsider some of our traditional definations in Europe, Australia, and North America and was based nitions. Brazil has few, if any, regions lacking ICUs capable on studies from high-income countries. For ICU investigators of providing mechanical ventilation, but much of the globe from these nations, the ability and need to assess the impact comprised low-income and resource-poor countries. ARDS of positive end-expiration pressures and gradations in arterial may be underestimated in regions with poor access. Rural Poj/FiOj ratio reflect the ability of resource-laden healthcare regions of low-income countries are associated with higher systems to respond to critical illness. The members of the task rates of poverty and poor health status that must overcome force for the Berlin Definition do not address the challenges obstacles of meager road conditions and inadequate comthat may arise in low-income countries, such as availability of munication services to reach an appropriate health facility mechanical ventilation itself. (9). The relative effect of positive end-expiratory pressure on syndrome definition may be moot at a hospital in Mulago, In an international context, we read the study by Caser Uganda, where a 12-bed ICU can only provide six patients et al (7) in this issue of Critical Care Medicine, conducted in the urban region of Vitoria, Espirito Santo in Southeast with mechanical ventilation in a 1,500 bed national-referral hospital and public university teaching hospital (10). In fact, Brazil. Brazil is an upper middle-income nation that is fifth in the entirety of Uganda, only 33 adult ICU beds are capable in population and geography worldwide. A prior Brazilian of providing mechanical ventilation (10, 11). Extrapolating studies and treatments may be difficult across borders. In the *See also p. 574. ARDSNet, critical care is delivered in specialized units with Keywords: adult; epidemiology; intensive care units; respiratory distress sophisticated equipment and a high staff-to-patient ratio syndrome; World Health within high-income countries (12). What works in Baltimore The authors have disclosed that they do not have any potential conflicts or Brazil may not be possible in Burkina Faso. of interest. For operational and analytical purpose, the World Bank Copyright © 2013 by the Society of Critical Care Medicine and Lippincott organizes the globe into high-, middle-, and low-income Williams & Wilkins countries. For ARDS epidemiology, we must likely do the DOI: 10.1097/CCM.0000000000000063
T
Critical Care Medicine
www.ccmjournal.crg
739
Editorials
same. Even where comparing modern ICUs across highincome countries like Japan and United States (13), heterogeneity occurs in patient population that may impact mortality. Pulmonary and nonpulmonary risk factors for ARDS vary dramatically between regions and carry their own variations in mortality (11). For example, globally, Streptococcal pneumonia manifests differently in resistance and virulence (14). Common ARDS risk factors in India are malaria and dengue fever, different diseases with different systemic effects and treatments (15). In resource-poor, low-income countries, erratic power and water supplies pose an additional challenge for ventilatory support (16). Aside from varying risk factors and available resources, access to an ICU in a timely fashion impacts mortality (10). Not surprisingly, it would be challenging to analyze the predictive ability of ARDS from Eastern to Western Europe, let alone across all World Health Organization (WHO) regions. Over the past decade, substantially more data for the descriptive epidemiology of risk factors for disease have become available in low- and middle-income countries (17). The size and diversity of the world's largest countries, such as Brazil, adds another dimension to the challenge of finding nationally representative information. The advent of more critical care societies and ICUs across WHO regions is step toward describing ARDS globally (12). The WHO's Global Burden of Disease 2010 study performed the largest systematic and comprehensive assessment on the global distribution of diseases and risk factors (18) but did not assess ARDS. We need to put it on the WHO's radar. The Global Sepsis Alliance has recently partnered with societies across Asia and Africa to address the burden of sepsis globally and support policies and recommendations (19). The next step in thinking globally about ARDS and creating a Global Health Initiative for ARDS may be to expand the membership community and incorporate leaders of critical care societies across continents to better study and treat ARDS around the world.
REFERENCES 1. Ashbaugh DG, Bigelow DB, Petty TL, et al: Acute respiratory distress in adults. Lancef 1967; 2:319-323 2. Bernard GR, Artigas A, Brigham KL, et al: The American-European Consensus Conference on ARDS. Definitions, mechanisms, relevant
740
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3.
4. 5.
6.
7
8.
9.
10.
11.
12.
13. 14.
15.
16.
17
18.
19.
outcomes, and clinical trial coordination. Am J Respir Crit Care Med 1994; 149:818-824 The Acute Respiratory Distress Network: Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network. N EngI J Med 2000; 342:1301 -1308 Rubenfeld GD, Caldwell E, Peabody E, et al: Incidence and outcomes of acute lung injury. N EngI J Med 2005; 353:1685-1693 Li G, Malinchoc M, Cartin-Ceba R, et al: Eight-year trend of acute respiratory distress syndrome: A population-based study in Olmsted County, Minnesota. Am J Respir Crit Care Med 2011 ; 183:59-66 Ranieri VM, Rubenfeld GD, Thompson BT, et al; ARDS Definition Task Force: Acute respiratory distress syndrome: The Berlin Definition. JAMA 201 2; 307:2526-2533 Caser EB, Zandonade E, Pereira E, et al: Impact of Distinct Definitions of Acute Lung Injury on Its Incidence and Cutcomes in Brazilian ICUs: Prospective Evaluation of 7,133 Patients. Crit Care Med 2014; 42:574-582 Azevedo LC, Park M, Salluh Jl, et al; The ERICC (Epidemiology of Respiratory Insufficiency in Critical Care) investigators: Clinical outcomes of patients requiring ventilatory support in Brazilian intensive care units: A multicenter, prospective, cohort study. Crit Care 2013; 17:R63 Mahmud Khan M, Hotchkiss DR, Berruti AA, et al: Geographic aspects of poverty and health in Tanzania: Does living in a poor area matter? Health Policy Plan 2006; 21:110-122 Kwizera A, Dünser M, Nakibuuka J: National intensive care unit bed capacity and ICU patient characteristics in a low income country. BMC Res Notes 201 2; 5:475 Wunsch H, Angus DC, Harrison DA, et al: Variation in critical care services across North America and Western Europe. Crit Care Med 2008; 36:2787-2793, el Prin M, Wunsch H: International comparisons of intensive care: Informing outcomes and improving standards. Curr Opin Crit Care 2012; 18:700-706 Sirio CA, Tajimi K, Taenaka N, et al: A cross-cultural comparison of critical care delivery: Japan and the United States. Chest 2002; 121:539-548 Hackel M, Lascols C, Bouchillon S, et al: Serotypa prevalence and antibiotic resistance in Streptococcus pneumoniae clinical isolates among global populations. Vaccine 2013; 31:4881-4887 Bhadade RR, de Souza RA, Harde MJ, et al: Clinical characteristics and outcomes of patients with acute iung injury and ARDS. J Postgrad Med 2011 ; 57:286-290 Dünser MW, Baelani I, Ganbold L: A review and analysis of intensive care medicine in the least developed countries. Crit Care Med 2006; 34:1234-1242 Abegunde DO, Mathers CD, Adam T, et al: The burden and costs of chronic diseases in low-income and middle-income countries. Lancet 2007; 370:1929-1938 Murray CJ, Ezzati M, Flaxman AD, et al: GBD 2010: A multi-investigator collaboration for global comparative descriptive epidemiology, ¿ancei 2012; 380:2055-2058 Stehr SN, Reinhart K: Sepsis as a global health problem-Why we need a global sepsis alliance. Shock 2013; 39(Suppl 1):3-4
March 2014 • Volume 42 • Number 3
Copyright of Critical Care Medicine is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
study enrolled 773 patients at multiple centers from the Brazilian Research in Intensive Care Network (BRICNet) across 12 states and found that ARDS developed in one third of patients requiring mechanical ventilation (8). In the current study. Caser et al (7) performed a population-based cohort Giora Netzer, MD, MSCE study over a 15-month period in 14 ICUs and screened 7,133 Division of Pulmonary and Critical Care Medicine; and patients for acute lung injury by AECC definition and ARDS Department of Epidemiology and Public Health by Berlin Definition. They reported a lower prevalence than University of Maryland the population-based cohort studies from United States. SevBaltimore, MD eral possibilities exist to explain this disparity. The ARDS definitions differ; they added 24 hours of mechanical ventilation to their definition for ARDS. The population differs he first syndromic definition of the acute respiraas well; patients with known risk factors for ARDS, includtory distress syndrome (ARDS) (1) was created by ing chronic liver disease, chronic renal failure, and chronic Americans to recognize a serious condition with high obstructive pulmonary disease, were excluded from analysis. mortality. The subsequent American European Consensus Conference (AECC) provided a uniform definition for the The source and vahdity of the population-based denominator is also unclear. syndrome (2), facilitating paradigm-shifting clinical trials performed by ARDS Network (ARDSNet), funded by the National This study shows that the Brazilian critical care commuHeart, Lung and Blood Institute (3). The consensus definition nity, in addition to being well organized (with two critical also facilitated rigorous population-based studies estimating care societies and its BRICNet), has and will continue to the prevalence of ARDS in the United States (4, 5). make important contributions to our understanding of lung More recently, the ARDS Definition Task Force refined the injury. This study also makes clear that rigorous epidemiosyndrome with the Berlin Definition, providing variables on logic assessment of ARDS is an international impetus, and acuity, requirements for mechanical ventilation, and stratificaour consideration of ARDS must extend past traditional tion of ARDS severity (6). The Berlin Definition came from borders. In assessing future studies from country to counan international consensus of researchers from industrialized try, we may need to reconsider some of our traditional definations in Europe, Australia, and North America and was based nitions. Brazil has few, if any, regions lacking ICUs capable on studies from high-income countries. For ICU investigators of providing mechanical ventilation, but much of the globe from these nations, the ability and need to assess the impact comprised low-income and resource-poor countries. ARDS of positive end-expiration pressures and gradations in arterial may be underestimated in regions with poor access. Rural Poj/FiOj ratio reflect the ability of resource-laden healthcare regions of low-income countries are associated with higher systems to respond to critical illness. The members of the task rates of poverty and poor health status that must overcome force for the Berlin Definition do not address the challenges obstacles of meager road conditions and inadequate comthat may arise in low-income countries, such as availability of munication services to reach an appropriate health facility mechanical ventilation itself. (9). The relative effect of positive end-expiratory pressure on syndrome definition may be moot at a hospital in Mulago, In an international context, we read the study by Caser Uganda, where a 12-bed ICU can only provide six patients et al (7) in this issue of Critical Care Medicine, conducted in the urban region of Vitoria, Espirito Santo in Southeast with mechanical ventilation in a 1,500 bed national-referral hospital and public university teaching hospital (10). In fact, Brazil. Brazil is an upper middle-income nation that is fifth in the entirety of Uganda, only 33 adult ICU beds are capable in population and geography worldwide. A prior Brazilian of providing mechanical ventilation (10, 11). Extrapolating studies and treatments may be difficult across borders. In the *See also p. 574. ARDSNet, critical care is delivered in specialized units with Keywords: adult; epidemiology; intensive care units; respiratory distress sophisticated equipment and a high staff-to-patient ratio syndrome; World Health within high-income countries (12). What works in Baltimore The authors have disclosed that they do not have any potential conflicts or Brazil may not be possible in Burkina Faso. of interest. For operational and analytical purpose, the World Bank Copyright © 2013 by the Society of Critical Care Medicine and Lippincott organizes the globe into high-, middle-, and low-income Williams & Wilkins countries. For ARDS epidemiology, we must likely do the DOI: 10.1097/CCM.0000000000000063
T
Critical Care Medicine
www.ccmjournal.crg
739
Editorials
same. Even where comparing modern ICUs across highincome countries like Japan and United States (13), heterogeneity occurs in patient population that may impact mortality. Pulmonary and nonpulmonary risk factors for ARDS vary dramatically between regions and carry their own variations in mortality (11). For example, globally, Streptococcal pneumonia manifests differently in resistance and virulence (14). Common ARDS risk factors in India are malaria and dengue fever, different diseases with different systemic effects and treatments (15). In resource-poor, low-income countries, erratic power and water supplies pose an additional challenge for ventilatory support (16). Aside from varying risk factors and available resources, access to an ICU in a timely fashion impacts mortality (10). Not surprisingly, it would be challenging to analyze the predictive ability of ARDS from Eastern to Western Europe, let alone across all World Health Organization (WHO) regions. Over the past decade, substantially more data for the descriptive epidemiology of risk factors for disease have become available in low- and middle-income countries (17). The size and diversity of the world's largest countries, such as Brazil, adds another dimension to the challenge of finding nationally representative information. The advent of more critical care societies and ICUs across WHO regions is step toward describing ARDS globally (12). The WHO's Global Burden of Disease 2010 study performed the largest systematic and comprehensive assessment on the global distribution of diseases and risk factors (18) but did not assess ARDS. We need to put it on the WHO's radar. The Global Sepsis Alliance has recently partnered with societies across Asia and Africa to address the burden of sepsis globally and support policies and recommendations (19). The next step in thinking globally about ARDS and creating a Global Health Initiative for ARDS may be to expand the membership community and incorporate leaders of critical care societies across continents to better study and treat ARDS around the world.
REFERENCES 1. Ashbaugh DG, Bigelow DB, Petty TL, et al: Acute respiratory distress in adults. Lancef 1967; 2:319-323 2. Bernard GR, Artigas A, Brigham KL, et al: The American-European Consensus Conference on ARDS. Definitions, mechanisms, relevant
740
w\A/\A/.ccmjournal.org
3.
4. 5.
6.
7
8.
9.
10.
11.
12.
13. 14.
15.
16.
17
18.
19.
outcomes, and clinical trial coordination. Am J Respir Crit Care Med 1994; 149:818-824 The Acute Respiratory Distress Network: Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network. N EngI J Med 2000; 342:1301 -1308 Rubenfeld GD, Caldwell E, Peabody E, et al: Incidence and outcomes of acute lung injury. N EngI J Med 2005; 353:1685-1693 Li G, Malinchoc M, Cartin-Ceba R, et al: Eight-year trend of acute respiratory distress syndrome: A population-based study in Olmsted County, Minnesota. Am J Respir Crit Care Med 2011 ; 183:59-66 Ranieri VM, Rubenfeld GD, Thompson BT, et al; ARDS Definition Task Force: Acute respiratory distress syndrome: The Berlin Definition. JAMA 201 2; 307:2526-2533 Caser EB, Zandonade E, Pereira E, et al: Impact of Distinct Definitions of Acute Lung Injury on Its Incidence and Cutcomes in Brazilian ICUs: Prospective Evaluation of 7,133 Patients. Crit Care Med 2014; 42:574-582 Azevedo LC, Park M, Salluh Jl, et al; The ERICC (Epidemiology of Respiratory Insufficiency in Critical Care) investigators: Clinical outcomes of patients requiring ventilatory support in Brazilian intensive care units: A multicenter, prospective, cohort study. Crit Care 2013; 17:R63 Mahmud Khan M, Hotchkiss DR, Berruti AA, et al: Geographic aspects of poverty and health in Tanzania: Does living in a poor area matter? Health Policy Plan 2006; 21:110-122 Kwizera A, Dünser M, Nakibuuka J: National intensive care unit bed capacity and ICU patient characteristics in a low income country. BMC Res Notes 201 2; 5:475 Wunsch H, Angus DC, Harrison DA, et al: Variation in critical care services across North America and Western Europe. Crit Care Med 2008; 36:2787-2793, el Prin M, Wunsch H: International comparisons of intensive care: Informing outcomes and improving standards. Curr Opin Crit Care 2012; 18:700-706 Sirio CA, Tajimi K, Taenaka N, et al: A cross-cultural comparison of critical care delivery: Japan and the United States. Chest 2002; 121:539-548 Hackel M, Lascols C, Bouchillon S, et al: Serotypa prevalence and antibiotic resistance in Streptococcus pneumoniae clinical isolates among global populations. Vaccine 2013; 31:4881-4887 Bhadade RR, de Souza RA, Harde MJ, et al: Clinical characteristics and outcomes of patients with acute iung injury and ARDS. J Postgrad Med 2011 ; 57:286-290 Dünser MW, Baelani I, Ganbold L: A review and analysis of intensive care medicine in the least developed countries. Crit Care Med 2006; 34:1234-1242 Abegunde DO, Mathers CD, Adam T, et al: The burden and costs of chronic diseases in low-income and middle-income countries. Lancet 2007; 370:1929-1938 Murray CJ, Ezzati M, Flaxman AD, et al: GBD 2010: A multi-investigator collaboration for global comparative descriptive epidemiology, ¿ancei 2012; 380:2055-2058 Stehr SN, Reinhart K: Sepsis as a global health problem-Why we need a global sepsis alliance. Shock 2013; 39(Suppl 1):3-4
March 2014 • Volume 42 • Number 3
Copyright of Critical Care Medicine is the property of Lippincott Williams & Wilkins and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
