Genetic and ethnic factors may explain some of the observed differences in the incidence and treatment of inflammatory bowel disease (IBD), but socio-economic status also plays a role, according to Justin Sewell, MD, MPH, assistant professor of medicine at the University of California, San Francisco.

“There are clearly disparities in care for IBD, but lower socio-economic status may be a greater contributor than race,” said Dr. Sewell, who discussed disparities in the delivery of IBD care during Saturday’s AGA Committee Sponsored Symposium The Roles of Genomics and Ethnicity in Inflammatory Bowel Disease. “There is minimal difference in outcomes of IBD by race, for example, but there is a 2.4-fold increase in mortality in the Medicaid population.”

A key indicator of poor outcomes is leaving the hospital against medical advice, he added. African-Americans are 30 percent more likely to leave the hospital against medical advice compared to Caucasians, while patients on Medicaid or who are uninsured are 4.5 times more likely to abandon hospital care.

Meanwhile, African-Americans are significantly less likely to receive surgical treatment for IBD, said Steven Brandt, MD, associate professor of medicine and director of the Meyerhoff Inflammatory Bowel Disease Center at The Johns Hopkins School of Medicine, Baltimore, MD. Genetics also play a role, he said.

“African-Americans tend to have less colonic disease than whites, so it may not be that much of a surprise that they are less likely to undergo surgery for IBD,” Dr. Brandt said. “We need to extend and expand genetic studies to all populations to improve our understanding and treatment of IBD.”

But accounting for ethnicity is complicated, noted Geoffrey Nguyen, MD, PhD, associate professor of medicine at the University of Toronto, Ontario, Canada.

“It’s a social construct more than a biological one,” he said. “The African-American genome is about 20 percent European, and Hispanics from the Western U.S. are quite different from Caribbean Hispanics in their genetic admixtures.”

Age can also make a difference in the incidence of IBD, said Maria Oliva-Hemker, MD, professor of pediatrics at The Johns Hopkins School of Medicine.

“Ulcerative colitis comes on first, then you see Crohn’s starting about six years of age,” she said. “We don’t have a great physiologic explanation for why this is occurring.”