Jim Kling

October 23, 2012

LAS VEGAS, Nevada — Results from a large cohort of African American patients with inflammatory bowel disease (IBD) reveal significant clinical differences between these patients and white patients.

Extraintestinal manifestations (EIMs) are more common in African Americans in both ulcerative colitis (UC) and Crohn's disease (CD), but there were no racial disparities in treatments or clinical trial enrollment, according to a study presented here at the American College of Gastroenterology (ACG) 2012 Annual Scientific Meeting and Postgraduate Course.

Some evidence suggests that the prevalence of IBD is increasing in minority groups, including African Americans, but there is limited understanding of how outcomes and phenotypic outcomes vary by race.

"IBD is commonly thought of as [typified by a] young, Caucasian patient, [but] the African American population really hasn't been studied. We wanted to clarify that," Anthony Sofia, MD, a resident in internal medicine at the University of Chicago, Illinois, who presented the research, told Medscape Medical News.

The researchers retrospectively reviewed the IBD registry at the University of Chicago. From the database, they analyzed self-identified race, IBD type, location, extent, surgery, family, smoking history, medications, extraintestinal manifestations, cancer and dysplasia history, and involvement in clinical trials. They then conducted a univariate chi-square analysis with a significance level of P < .10.

Among patients with CD, there were 797 whites and 86 African Americans. Among patients with UC, 345 were white and 19 were African American. In the CD group, African Americans had higher rates of joint symptoms (31.2% vs 20.1%; P = .015) and pyoderma gangrenosum (3.5% vs 1.1%; P = .073). The rate of ileal involvement was lower among African American patients with CD (45.4% vs 60.4%; P = .007), but rates of upper gastrointestinal, jejunal, colonic, or perianal disease did not differ.

In the UC group, African Americans had higher rates of extraintestinal manifestations overall (42.1% vs 20.8%; P = .029), joint symptoms (26.3% vs 12.1%; P = .072), and pyoderma gangrenosum (5.3% vs 0.6%; P = .028). The extent of disease was the same in both populations. There were also no significant differences in medication use; clinical trial enrollment; prevalence of dysplasia or cancer; or surgical, family, or smoking histories.

"The African American population that we were looking at has a more atypical disease presentation, with differences in extraintestinal manifestations and a lower presence of ileal disease. The next step is trying to tease out, is this due to a socioeconomic difference, is this an exposure that we're looking at, or more of a genetic variable? We know that the African American population tends to be more genetically diverse than the Caucasian population," Dr. Sofia said.

The results should be useful to physicians, according to Sunanda Kane, MD, a professor of medicine at Mayo Clinic in Rochester, Minnesota. "If you have a non-white person sitting in front of you, make sure you ask about itchy eyes, joint aches, skin rashes.

"It also highlights how at least the investigators in Chicago are colorblind in terms of offering the same kind of treatment strategies, and there's no preferential treatment or substandard treatment based on race," Dr. Kane told Medscape Medical News.

Dr. Sofia and Dr. Kane have disclosed no relevant financial relationships.

American College of Gastroenterology (ACG) 2012 Annual Scientific Meeting and Postgraduate Course. Abstract 957. Presented October 22, 2012.