ATS 2009: Blacks at Higher Risk for Acute Lung Injury

Kristina Rebelo

May 21, 2009

May 21, 2009 (San Diego, California) — Black Americans are at disproportionate risk of developing acute lung injury (ALI), although their chances for in-hospital mortality are about the same as for white patients, according to a study released here at the ATS 2009: the American Thoracic Society International Conference.

Dr. Sara Erickson

"People oftentimes don't have access to care due to a lack of insurance or sometimes don't seek care due to limited health literacy," lead investigator Sara Erickson, MD, assistant professor of pulmonary, allergy and critical care medicine at Emory University School of Medicine in Atlanta, Georgia, told Medscape Pulmonary Medicine after her presentation.

Researchers estimated the incidence of ALI among all black and white Americans from 1992 to 2005 using the National Hospital Discharge Survey (NHDS) database. They looked for cases of ALI, defined by the presence of International Statistical Classification of Diseases and Related Health Problems (ICD)-9 codes for respiratory failure or pulmonary edema (they excluded at-risk conditions, such as sepsis, pneumonia, aspiration, and trauma). The NHDS provided Dr. Erickson's research group with the opportunity for an up-close study of the relationship between race and the incidence of ALI.

Dr. Erickson said their study-design methods were "slightly unconventional," but using an annual survey of 500 nonfederal acute-care hospitals in the United States, which provided a 1% sample of hospital discharges (350,000 annually), and demographic data and ICD-9 codes abstracted from discharge records during the study period (from 1992 to 2005) were important factors, which all contributed to a statistically sound conclusion.

Study results found that ALI cases among black Americans had a significant temporal increase, from 23.0 cases per 100,000 in 1992 to 78.8 cases per 100,000 in 2005; among white Americans, the annual incidence of ALI increased from 12.2 cases per 100,000 in 1992 to 36.9 cases per 100,000 in 2005.

Using 2000 US Census data, the researchers said that the average annual incidence of ALI during the 13-year period was 48 cases per 100,000 for black Americans and 25.7 cases per 100,000 white Americans (relative risk, 1.88 for black Americans; 95% confidence interval, 1.45 - 2.67) There were no statistically significant differences in overall in-hospital mortality (37.9% for white Americans vs 36.3% for black Americans).

Black Americans: Nearly Double the Rate of ALI as Whites

Even after the more than tripling of ALI among white Americans between 1992 and 2005, blacks were still more than twice as likely as whites to suffer from ALI, and they continue to make up a significant proportion of ALI sufferers. Dr. Erickson suggested that the higher risk for black Americans (nearly double the incidence rate) could be due to the fact that black Americans, according to earlier studies, have an increased risk of developing sepsis, compared with whites. In addition, blacks have a higher burden of comorbidities, including immunocompromising conditions, such as diabetes and HIV/AIDS, both of which increase the chance of pneumonia.

"I don't think it's about doctors intentionally being racist," said Dr. Erickson. "I think our findings reflect institutionalized racism in terms of the issues surrounding access to care and the quality of hospitals where minorities receive care." Dr. Erickson, who graduated from Yale University School of Medicine in New Haven, Connecticut, and completed her residency and fellowship at the University of California, San Francisco, is on staff at Grady Hospital in Atlanta, the largest public hospital in the state of Georgia. It is considered to be one of the premier public hospitals in the Southern United States.

"Our results beg the question: Why?," Dr. Erickson said during her presentation. "I would be astounded if it were just 1 reason; it's probably a combination of things — I think the social underpinnings of racial disparities are very complex."

She listed the following theories as to why black Americans are at higher risk of developing ALI:

  • Higher probability of having an at-risk condition with double the risk for sepsis

  • Lack of primary care

  • Lack of insurance

  • Later presentation for medical treatment with greater severity of illness

  • Differences in quality/processes of care with less intense care at lower-quality hospitals.

 

The study limitations were that there were no published studies that validated the use of ICD-9 codes for the diagnosis of ALI, although the sensitivity and specificity of their ALI definition should not affect comparison of black and white Americans. In addition, there was no multivariable adjustment, and no consideration given to socioeconomic status, insurance status, and severity of illness. Future studies, she said, should focus on uncovering the cause of the increased risk with a prospective study on the association between race and ALI in a large diverse American population measuring socioeconomic, insurance status, comorbid conditions, and alcohol use.

Dr. Brent Kinder

"Finally, we need to look at the quality of care at the hospitals and institutions that are providing care to minority patients," said Dr. Erickson, who added that she has hope that the new administration will overhaul the system so that "everyone can have insurance and a primary-care provider."

Commenting after the presentation was Brent Kinder, MD, assistant professor of pulmonary and critical care medicine at the University of Cincinnati in Ohio. "This is a big problem and an important issue, with policy implications for stakeholders interested in reducing health disparities in diseases like sepsis or ALI among minority patients," said Dr. Kinder.

He added: "The policy implication in [the study by Dr. Erickson and her colleagues] is that in the past several decades, indigent-care hospitals have not been supported in a way that would allow for equitable care."

Dr. Erickson and Dr. Kinder have disclosed no relevant financial relationships.

ATS 2009: American Thoracic Society International Conference: Abstract 1743. Presented May 19, 2009.

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