Study reveals disturbing increase in the incidence of severe diverticulitis among Americans under the age of 50

A comprehensive analysis of more than 5.2 million hospitalizations reveals a troubling increase in cases of severe diverticulitis among Americans under the age of 50.

The analysis, led by researchers from UCLA and Vanderbilt University and published in the journal, reviewed hospital admissions of adult patients with diverticulitis in the U.S. from 2005 to 2020. The researchers found that the proportion of younger patients admitted with complicated diverticulitis – a subtype of diverticulitis that includes abscesses, perforations or other serious complications – increased from 18.5% to 28.2%, a 52% increase compared to the previous study.

The study’s first author, Shineui Kim of UCLA Health, and principal investigator Dr. Aimal Khan of Vanderbilt University, said the findings indicate growing public health concerns among young Americans, as this population has seen a similar increase in colorectal cancer rates.

“We are seeing a significant change in hospitalizations for severe diverticulitis,” said Kim, a fourth-year medical student at the David Geffen School of Medicine at the University of California, Los Angeles. “Traditionally, this condition has been thought of as a disease of older people, but our data shows that it is increasingly affecting younger Americans and often has more complex symptoms.”

Diverticulitis causes small pouches to form in weak areas of the colon wall, which can lead to stomachachebloating, bleeding, constipation and diarrhea among other symptoms. The disease is thought to be more common in older people and less common in people under 40 years of age.

However, a University of California, Los Angeles analysis of the National Inresident Sample, the largest publicly available database covering all payers in the United States, showed a changing trend.

Of the 5.2 million patients hospitalized with diverticulitis between 2005 and 2020, approximately 16%, or 837,195, were classified as “early onset” cases, occurring in patients less than 50 years of age. Of these early-onset cases, the number of people admitted to hospital with complicated diverticulitis increased from 18.5% to 28.2%.

Kim said this represents a significant burden of disease in a demographic that has historically been at lower risk.

Despite the increase in the number of complex cases, treatment strategies have evolved. During the study period, the percentage of younger patients requiring colectomy to surgically remove part of the large intestine decreased from 34.7% to 20.3%. Kim said this suggests that doctors are effectively treating more cases using a conservative approach.

Kim said the analysis showed other differences between younger and older patients with diverticulitis. Compared to older patients, younger patients had:

• Lower mortality rates
• Shorter hospital stays (0.28 days shorter on average)
• Lower hospitalization costs ($1,900 less per admission)

However, younger patients were more likely to require intervention, with a 29% greater risk of requiring colectomy and a 58% greater risk of requiring percutaneous drainage compared to older patients.

Although younger patients generally have better survival outcomes and shorter hospital stays, they are paradoxically more likely to require invasive interventions. This suggests that their disease may be more aggressive or that treatment approaches vary depending on the patient’s age and overall health.”

Shineui Kim of UCLA Health

Researchers said further research into potential causes of the increasing burden of early-onset diverticulitis is poorly understood. With a similar increase seen in this population of colorectal cancer,

“There is little understanding of why we are seeing this increase among younger patients,” Kim said. “We urgently need additional research to determine what is driving these trends, whether they are dietary factors, lifestyle changes, obesity rates or other environmental influences.”