Pitt Team Finds Blacks Have Greater Risk for Infection, Organ Injury

Findings in JAMA Could Explain Disparities in Severe Sepsis Rates

PITTSBURGH, June 22 – Black people are at greater risk than whites for severe sepsis, a condition where overwhelming infection can lead to deadly consequences, because blacks are both more susceptible to getting infections and more likely to develop organ injuries, say researchers at the University of Pittsburgh School of Medicine. The findings are available today in the Journal of the American Medical Association.

The study also suggests that both community- and hospital-based interventions could help alleviate such racial disparities, said lead author Florian B. Mayr, M.D., M.P.H., research fellow, Department of Critical Care Medicine, University of Pittsburgh. For example, immunization guidelines could be modified to encourage administration of pneumococcal vaccine to younger black people to prevent some lung infections. Narrowing quality gaps across hospitals in the care of patients who are hospitalized for an infection also could reduce racial disparities in severe sepsis.

Annually, more than 750,000 Americans develop severe sepsis, defined as systemic infection plus organ injury, and 1 out of every 4 individuals who develop it will die during their hospital stay. The researchers examined 2005 discharge data from hospitals in Arizona, Florida, Massachusetts, Maryland, New Jersey, New York and Texas, representing a quarter of the American population, as well as infection-related emergency department visits data from the 2003-2007 National Hospital Ambulatory Care Survey.

After controlling for age and sex, they found that compared to whites, blacks had a 67 percent higher rate of severe sepsis, and 80 percent higher mortality. That greater likelihood was explained by an infection rate that was 47 blacks and 34 whites per 1,000 people, and the odds of a black person developing acute organ dysfunction was 29 percent higher than whites.

“Given that research has shown that black people are less likely to be hospitalized as a result of an emergency room visit, these results could well be an underestimate,” Dr. Mayr noted.

As an example of how a community-based intervention could reduce such disparities, the researchers calculated the potential impact of modifying vaccination guidelines to prevent pneumonia caused by Strep pneumonia or pneumococcus, which can progress to a systemic infection and subsequent organ injury. Currently, pneumococcal vaccination is recommended for people 65 and older, younger adults with certain chronic illnesses and small children.

“If we also vaccinated black adults younger than 65, we might be able to avoid a significant number of cases of severe sepsis in this population,” said Sachin Yende, M.D., M.S., assistant professor of critical care medicine, University of Pittsburgh, and the study’s corresponding author. “Our analysis showed that 25 percent of pneumococcal infections occurred among 18- to 65-year-olds who had no other illnesses, so they would not have been considered for vaccination.”

Racial disparities in severe sepsis are likely due to socio-economic and other factors. Community-based interventions, such as better management of chronic disease, as well as hospital-based approaches, must be part of an overall strategy to address this problem, he added.

The researchers are now working on identifying biologic differences that might also contribute to differences in susceptibility to infection and risk for organ dysfunction.

Other authors of the paper include Walter T. Linde-Zwirble, of Pitt and ZD Associates, Pekasie, Pa.;  Octavia M. Peck-Palmer, Ph.D., Amber E. Barnato, M.D., M.S., M.P.H., Lisa A. Weissfeld, Ph.D., and Derek C. Angus, M.D., M.P.H., all of Pitt.

The study was funded by the National Institutes of Health.

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University of Pittsburgh School of Medicine

As one of the nation’s leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997 and now ranks fifth in the nation, according to preliminary data for fiscal year 2008. Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region’s economy. For more information about the School of Medicine, see www.medschool.pitt.edu.

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