Photo Credit: Aelitta
A study examining 20 years of data shows that race, ethnicity, and geography impact disease severity in patients with IBD.
“The incidence and prevalence of IBD—including Crohn’s disease and ulcerative colitis—has been increasing worldwide, including among ethnicities and nationalities where it was once rare,” Ali Khalessi, MD, and Lea Ann Chen, MD, explain. “Therefore, it has become even more important to understand the underlying mechanisms of the disease, as well as attempt to identify population groups that are most at risk of severe disease phenotypes.”
A better understanding of how race and ethnicity influence IBD manifestations will improve the information about prognosis that clinicians provide their patients, Dr. Khalessi and Dr. Chen note. “Further, understanding the impact of immigration status on IBD manifestations will help us tease apart the environmental and genetic components of the disease.”
For a study published in Gastro Hep Advances, Dr. Khalessi, Dr. Chen, and colleagues performed a single-center retrospective review of all patients with IBD treated between 1997 and 2017. The study team used logistic regression modeling to compare disease onset, treatment, and outcomes by race (White, Black, Hispanic, and Asian) and immigration status (US-born vs foreign-born).
Findings in Black Patients & Foreign-Born Patients
The analysis included 577 patients, with the following breakdown by race:
- 29.8% White
- 27.4% Hispanic
- 21.7% Black
- 13.0% Asian
The researchers found that Black patients were more likely to be diagnosed with Crohn’s disease (OR, 1.75; 95% CI, 1.10-2.77). These patients were also more likely to undergo an IBD-related intestinal resection (OR, 2.49; 95% CI, 1.40-4.50).
Patients born outside the United States in predominantly low incidence countries were more likely to be diagnosed with ulcerative colitis compared with patients born in the United States (OR, 1.77; 95% CI, 1.04-3.02). Foreign-born patients were less likely to be diagnosed prior to age 16 (OR, 0.19; 95% CI, 0.8-0.41), to receive intestinal resections (OR, 0.39; 95% CI, 0.19-0.83), to be treated with biologics (OR, 0.43; 95% CI, 0.25-0.76), and to exhibit dermatologic manifestations of IBD (OR, 0.12; 95% CI, 0.03-0.41).
“It is important to stress that the more severe phenotype observed among US-born Black patients, which was present even among our uniformly underinsured and uninsured patient population,” Dr. Khalessi and Dr. Chen say (Table), suggesting that the finding is not due to decreased access to care or socioeconomic status.
“We also noted a less severe disease phenotype among foreign-born patients. Studies from other groups demonstrating an increase in disease phenotype severity among immigrants to Western countries and their children implicates a possible environmental component driving disease severity.”
The study also demonstrated an increased risk for IBD in men among Asian patients. “This increased risk among Asian men—a finding noted in other studies from Asia as well—indicates a possible protective genetic component among Asian women,” Dr. Khalessi and Dr. Chen note.
Implications for Clinicians & Directions for Future Research
The findings show that, among patients with IBD, “certain ethnic groups, regardless of socioeconomic status, appear to be at risk for developing a more severe disease phenotype,” Dr. Khalessi and Dr. Chen continue.
“Further, our results seem to indicate that patients who are native-born to Western countries/cultures may also be included in this higher risk group when compared with recent immigrants from outside of North America or Western Europe.”
For clinicians, this means that patients from these subgroups may benefit from closer surveillance and a more aggressive management strategy in terms of indications for biologic or small-molecule therapies, the researchers note.
The findings also open doors to future research.
“There are many unanswered questions remaining when it comes to the genetic and environmental drivers of IBD phenotype,” Dr. Khalessi and Dr. Chen explain. “In particular, more information is needed regarding the timeframe in which risk increases after immigration. Long-term studies examining ethnically diverse patient groups, while controlling for socioeconomic determinants of health, after they immigrate to western countries are unfortunately limited.”
