Diverticulitis Increases as Diverticular Bleeding Decreases

Wheat C, Parasa S, Strate L. Epidemiologic trends for diverticulitis and diverticular bleeding: one increasing, one decreasing. Program No. P929. ACG 2013 Annual Scientific Meeting Abstracts. San Diego: American College of Gastroenterology.

Epidemiologic trends for diverticulitis and diverticular bleeding show the prevalence of the former is increasing over time while that of the latter is on the decline. These findings from an analysis of the largest publicly available US inpatient care database were presented on October 14, 2013, at the American College of Gastroenterology Annual Scientific Session.

“The prevalence of one disease (diverticulitis) is decreasing while the other (diverticular bleeding) is increasing, suggesting that the etiopathogenesis of these disorders is different,” Lisa Strate, MD, of Harborview Medical Center in Seattle told ConsultantLive. “Both diverticulitis and diverticular bleeding are more common in women. Diverticulitis is more common than diverticular bleeding except in the elderly. Diverticular bleeding is uncommon in individuals younger than 50 years.”

Dr Strate and colleagues analyzed data from the National Inpatient Sample (NIS) of the Health Care and Utilization Project from years 2000 to 2010, which is the largest publicly available database of its kind in the United States. They identified adult patients with a principal discharge diagnosis of diverticular bleeding or diverticulitis. Using US Census and Intercensal data for each year, they calculated individual age, gender, and race-adjusted prevalence rates.

The researchers found the prevalence of diverticular bleeding decreased over the 10-year time span from 32.6/100,000 in 2000 to 27.1/100,000 in 2010. In comparison, the prevalence of diverticulitis increased over the majority of the 10-year time span, with a peak in 2008. The prevalence was 74.1/100,000 in 2000, 95.7/100,000 in 2008, and 91.7/100,000 in 2010. The prevalence of diverticulitis and diverticular bleeding was higher in females than in males throughout the period of observation. The prevalence of diverticular bleeding was highest in African Americans (34.4/100,000 in 2010), whereas the prevalence of diverticulitis was highest in whites (75.5/100,000 in 2010).

Why the divergent trends? The answer may lie in environmental factors. “Obesity, diet, physical activity, smoking, and non-steroidal anti-inflammatory drug use,” says Dr Strate, “are known risk factors for diverticulitis and diverticular bleeding, and likely play a role in these trends.”  She adds, “These same risk factors have also been associated with diverticular bleeding, so it is less clear why the incidence of bleeding is decreasing. However, diverticulitis and diverticular bleeding are felt to evolve through different biologic pathways.”

Hormonal differences could explain the sex differences. “In one study, use of oral contraceptives and hormone replacement therapy was positively associated with hospitalization for diverticular disease,” says Dr Strate. She has recently found that genetics play an important role in diverticular disease so “inherited factors could explain racial differences, as could different environmental exposures,” she said.

These data are unlikely to change the management of diverticulitis or diverticular bleeding, and are most relevant to public health experts to guide future research regarding risk factors for diverticular complications. “However, they may be helpful to providers and patients in terms of understanding and explaining these disorders and their trends,” said Dr Strate.