Some previous research has explained the fact that black and Hispanic children are more likely to have their appendix rupture by pointing to signs of poor health care access, including being uninsured, having public assistance insurance or having a low socioeconomic status.

But the latest report finds that the main reasons for these disparities "are anybody's guess," said lead author Dr. Edward Livingston, a professor at the University of Texas Southwestern Medical Center in Dallas who analyzed more than half a million hospital admissions for appendicitis.

The condition means inflammation of the appendix, a pocket of tissue attached to the intestine, and in some cases the little organ can rupture. To prevent severe infections, quick surgery is needed to remove the appendix before it bursts.

Among adults, Livingston and a colleague found no differences between white, black or Hispanic patients in the proportion of those whose appendix had burst before they could get surgery.

Children, however, did show differences depending on their race: 27 out of every 100 white kids, 35 out of every 100 black kids, and 36 out of every 100 Hispanic kids had a ruptured appendix.

Medicaid insurance -- the government-subsidized health insurance for the poor -- was associated with having a burst appendix, as was poverty itself.

But when Livingston and his partner looked at the numbers more closely, they found that health insurance explained only 12 percent and family income explained only seven percent of the difference between the white and black children.

Between white and Hispanic kids, age explained about one third of the difference, with Hispanic children's younger ages putting them at a higher risk of having a ruptured appendix.

Income and health insurance contributed about the same to the differences as between white and black kids.

"Using a very large database we found that the factors that go along with health care access, like minority status or low socioeconomic status or unfavorable health insurance, really didn't explain the difference in perforation rates at all," Livingston told Reuters Health.

Livingston said it's unclear what might be the main contributors to the higher rates of appendix rupture, but that genetics could be a culprit.

Certain genes might make people more susceptible to having a burst appendix, and perhaps those genes are more frequent among black or Hispanic populations, he speculated.

Dr. Benedict Nwomeh, a pediatric surgeon at Nationwide Children's Hospital in Columbus, Ohio, said there is little evidence at this point to support the idea that biological differences put black or Hispanic kids at a higher risk of a ruptured appendix.

"The useful contribution of this paper is to say, 'we have this disparity, and if we're trying to solve this, we shouldn't be looking only at correcting disparities in insurance or income,'" said Nwomeh, who was not involved in this study.

The researchers write in their report, published in the Archives of Surgery, that appendix rupture has been used as an indicator of poor health care access.

Livingston said that a more appropriate marker of health care barriers is preventive services, such as cancer screening and counseling to quit smoking.

"Those are the kinds of rates that will be sensitive to access," he said.

SOURCE: bit.ly/ysd3Y9 Archives of Surgery, January 2012.

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