Study: Prevalence of IBS Exceeds Previous Estimates

A large nationwide survey of 89,000 people conducted by Cedars-Sinai investigators found the prevalence of irritable bowel syndrome (IBS) to be higher than previously reported: 6.1% compared with 4.7% to 5.3% in studies of significantly smaller sample sizes.

The results of the representative study are published in the journal Gastroenterology.

“This new study is among the largest population-based evaluations of IBS epidemiology. The results reveal that the condition is more prevalent than previously thought and varies by race and ethnicity,” said the study’s corresponding author, Brennan Spiegel, MD, MSHS, director of Health Services Research and the Dorothy and George Gourrich Chair in Digital Health Ethics at Cedars-Sinai.

In May and June of 2020, investigators conducted online surveys of adults age 18 and older. A large cross section of people living in the U.S. were asked to complete the Rome IV IBS questionnaire and the National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS) survey to assess the presence and severity of their gastrointestinal symptoms.

“We wanted to update our understanding of how common IBS is in the U.S. and to get a sense of the associated burden of the illness. Because diagnosis is symptom-based, we used the Rome IV validated IBS questionnaire to survey respondents about their abdominal pain and changes in bowel habits. We also used the PROMIS survey to see what other symptoms they were experiencing,” said gastroenterologist and co-first author of the study Christopher Almario, MD, MSHPM, who is also an assistant professor of Medicine at Cedars-Sinai.

In addition to the significant size of the study cohort, investigators point out there have been few large-scale studies looking at racial and ethnic differences in IBS.

“Our findings showed that non-Hispanic Black people, Hispanics and non-Hispanic Asian people all were less likely to have IBS when compared to non-Hispanic white people,” said Almario.

“But some of the non-white participants who did have IBS experienced more severe symptoms. For example, Hispanics and non-Hispanic Black people with a form of IBS where diarrhea is common had more severe belly pain than their non-Hispanic white counterparts,” said Almario.

Since the prevalence of IBS appears to be on the rise, Almario suggests physicians may be seeing more patients with associated symptoms in their clinics.

“In addition to abdominal pain and changes in bowel habits, patients with IBS may experience bloating, excess gas and heartburn. It is important for healthcare providers to take a thorough patient history in order to identify and manage these treatable symptoms,” said Almario.

According to the study authors, the COVID-19 pandemic may have played a role in the increased prevalence of IBS, and they are performing additional data analysis to examine the potential connection.

“It is possible that both direct infection with the virus that causes COVID-19 and the psychological stress associated with living through a pandemic contributed to the rise in IBS prevalence through a number of mechanisms worthy of further investigation,” said Spiegel.

DOI: https://doi.org/10.1053/j.gastro.2023.08.010

Funding: Support for this study was provided by Ironwood Pharmaceuticals in the form of an institutional research grant to Cedars-Sinai.

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