Blacks Seem More Vulnerable to Deadly Blood Infection
TUESDAY June 22, 2010 -- Black patients are more likely to develop the life-threatening blood infection sepsis and have a greater chance of dying from it than whites, new research suggests.
In severe sepsis, a bacterial or fungal infection overwhelms the body's immune system, causing a disruption of normal processes in the blood. When this occurs, small blood clots form, blocking blood flow to the organs, which can lead to organ damage, organ failure and death.
Researchers from the University of Pittsburgh examined hospital discharge data from seven states in 2005 and emergency department visits during a five-year period between 2003-2007 from the National Hospital Ambulatory Care Survey. Of 8.6 million hospitalizations for reasons other than childbirth, they identified more than 2.2 million cases of infections. Of those, nearly 17 percent, or about 380,000, also involved organ dysfunction, a hallmark of severe sepsis.
The investigators found that black patients had a higher risk of being hospitalized for an infection than white patients. About 47 per 1,000 blacks were hospitalized due to infection, compared to 34 per 1,000 whites.
The greater incidence of infections translated into a higher risk for sepsis. Black patients had a 67 percent higher severe sepsis hospitalization rate than non-Hispanic whites -- the incidence was about 9.4 per 1,000 blacks compared to 5.6 per 1,000 whites.
Because blacks were both more likely to be hospitalized for an infection, and because severe sepsis occurred more frequently among blacks, black patients were 80 percent more likely to die from it, according to the study published in the June 23/30 issue of the Journal of the American Medical Association.
Severe sepsis sickens about 750,000 people in the United States each year. About 28 percent of those who develop severe sepsis die, according to estimates cited in the study. Previous research has shown that people who have chronic medical conditions are more prone to sepsis.
In the current research, about 24 percent of blacks who were hospitalized for infection had diabetes and 3.5 percent had chronic kidney disease, compared to roughly 18 percent and 2.6 percent for whites, respectively.
To combat sepsis, the study authors recommended steps to reduce the infections that trigger sepsis in the first place.
The most common infections among those with sepsis were respiratory infections, such as bacterial pneumonia, which accounted for about one-third of cases in the study. Other common sepsis-inducing infections included urinary tract, abdominal, wounds and soft tissue infections.
Current recommendations call for those aged 65 and older or those under 65 with chronic conditions such as diabetes to receive a pneumococcal vaccination. But to reduce the risk of sepsis in blacks, it's possible vaccine recommendations should be revised to encourage younger blacks to get vaccinated, the researchers noted.
Black patients hospitalized for infections tended to be younger than whites. The average age for blacks with severe sepsis was 62, compared to 70 for whites, the research showed.
The same was true for pneumonia, with about 45 percent of whites who developed pneumonia under the age of 65, compared to about 74 percent of blacks.
Further analysis showed that if everyone was vaccinated according to the current guidelines, the vaccine would miss about 25 percent of blacks who develop pneumonia compared to only 13 percent of whites.
Better care for chronic diseases such as diabetes and kidney disease may also help ward off infections that lead to sepsis, the study authors suggested.
"People who tend to develop infections more often have diabetes and chronic kidney disease, and studies have shown blacks are more likely to have these chronic conditions earlier in life," said study co-author Dr. Sachin Yende, an assistant professor of critical care medicine at University of Pittsburgh. "The answer to reducing racial discrepancies in severe sepsis will require strategies in multiple areas: vaccination changes and improved management of chronic conditions such as diabetes and kidney disease."
Researchers could not say to what degree socioeconomic factors might lead to higher incidence of infection and sepsis in blacks. In addition, it's possible there are biological differences in how blacks and whites respond to infections that make blacks more likely to develop sepsis, the researchers noted.
Dr. Omar Lateef, director of the medical intensive care unit at Rush University Medical Center, said the risk of sepsis, especially among those with chronic conditions, should be taken very seriously. Even those who survive severe sepsis "can have a very long, drawn-out course of recovery. It's a huge stress for your body, and some people may never fully recover," Lateef said.
The reasons why chronic conditions such as diabetes raise the risk aren't fully understood, Lateef said. But patients can help protect themselves from sepsis, he added.
"You have to take care of yourself, get your vaccines up to date, take all your medicines and regularly check in with your primary care physician," Lateef suggested.
For doctors, "doing a better job with outpatients is going to be the best thing they can do to improve mortality in the inpatient population," Lateef said.
The Society of Critical Care Medicine has more on sepsis.
Posted: June 2010