A comprehensive new analysis estimates that 2.4 million Americans have been diagnosed with inflammatory bowel disease (IBD), and up to 56,000 new cases are diagnosed each year.

“The prevalence of IBD in the United States has been gradually increasing over the last decade, and thus the burden of caring for IBD is likely to increase as life expectancy increases,” co-principal investigator Andrés Hurtado-Lorenzo, PhD, senior vice president, Translational Research and IBD Ventures, Crohn’s & Colitis Foundation, told Medscape Medical News.

These data provide “an initial step toward optimizing healthcare resources allocation and improving care of individuals with IBD,” Manasi Agrawal, MD, a gastroenterologist at Mount Sinai Hospital, New York City, who wasn’t involved in the study, told Medscape Medical News.

The study was published online July 20 in Gastroenterology.

For the federally funded study, researchers pooled data from commercial, Medicare, and Medicaid insurance plans to derive a population-based estimate of the incidence and prevalence of IBD throughout the United States.

“In essence, we consider this to be the most extensive study of the incidence and prevalence of IBD in the United States based on physician-diagnosed IBD, which is representative of nearly the entire US population with health insurance,” Hurtado-Lorenzo said.

Trends Identified

Key findings from the study include:

• The age- and sex-standardized incidence of IBD was 10.9 per 100,000 person years.

• The incidence of IBD peaks in the third decade of life, decreases to a relatively stable level across the fourth to eighth decades, and declines further beyond age 80.

• Ulcerative colitis is slightly more common than Crohn’s disease in most age groups, except in children, among whom this trend is reversed.

• The adjusted prevalence data show that IBD has been diagnosed in more than 0.7% of Americans, with 721 cases per 100,000, or nearly 1 in 100.

• Historically, IBD was slightly more common in men. Now it’s slightly more common in adult females and male children.

• IBD prevalence is highest in the Northeast and lowest in the western region of the United States.

• The overall prevalence of IBD increased gradually from 2011 to 2020.

“Environmental variables, such as ultra-processed foods, pollution, and urbanization, to name a few, are implicated in IBD risk. Shifts in our modern environment and improving diagnostics may be two reasons why we see rising trends in IBD,” Agrawal, assistant professor of medicine at the Icahn School of Medicine at Mount Sinai, told Medscape Medical News.

Prevalence Highest Among Whites

The data also point to significant differences in prevalence among different racial groups, with Whites having a rate of IBD that is seven times higher than Blacks, six times higher than Hispanics, and 21 times higher than Asian Americans.

The prevalence of IBD per 100,000 population was 812 in Whites, 504 in Blacks, 403 in Asian Americans, and 458 in Hispanics.

“It’s important to note that the reasons for ethnic disparities in IBD prevalence are complex and multifactorial, and further research is needed to better understand the specific mechanisms underlying these disparities,” Hurtado-Lorenzo said.

Factors that could contribute to this disparity include genetic and environmental factors, socioeconomic factors, healthcare disparities, differences in disease awareness and reporting, and underdiagnosis in some populations.

The data suggest a lower prevalence of IBD among children with Medicaid insurance, “which underscores the need for further investigation into the influence of social determinants of health on IBD care,” Hurtado-Lorenzo noted.

Insights Important for Planning

Because of the fragmented nature of the healthcare system, it’s been challenging to get an accurate estimate of how many patients in the United States have IBD, Ashwin Ananthakrishnan, MD, MPH, a gastroenterologist with Massachusetts General Hospital and Harvard Medical School in Boston, told Medscape Medical News.

“The authors and involved organizations are to be fully complemented on this really ambitious and important study. Having an idea of how common IBD is and how it is likely to increase in prevalence is important for resource planning for organizations and healthcare systems,” said Ananthakrishnan, who was not involved in the study.

Although IBD incidence and prevalence is lower in non-White populations, there is still a “sizeable burden of IBD in those groups and it’s important to understand the implications of that in terms of disease biology, treatment availability, disparities, and access to care,” he added.

“With the aging of the population and increasing prevalence, it is also important to understand that the ‘face of IBD’ in the coming decades may be different than what we traditionally have estimated it to be. This is also important to incorporate in decision making,” Ananthakrishnan said.

Funding for the study was provided by the Centers for Disease Control and Prevention. Hurtado-Lorenzo, Agrawal, and Ananthakrishnan have no relevant disclosures.

Gastroenterol. Published online July 20, 2023. Abstract

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