CHARLOTTE, N.C.—Diverticular disease is among the most searched topics on the American College of Gastroenterology’s patient website, eliciting more web traffic than colon polyps or belching. About half of Americans 60 years of age and older have diverticulosis, and about 5% of them will develop diverticulitis. These people have questions. Sometimes their providers do, too.
In a presentation at the ACG’s 2022 annual meeting, Neil Stollman, MD, a co-author of the American Gastroenterological Association’s guideline on diverticular disease (Gastroenterology 2015;149[7]:1944-1949) discussed many practical issues related to causation, treatment and prevention of the condition.
Lifestyle Factors
According to Dr. Stollman, the chief of the Division of Gastroenterology at Alta Bates Summit Medical Center, in Oakland, Calif., and an associate clinical professor of medicine at UCSF, maintenance of a “low-risk lifestyle” can effectively halve one’s risk for developing diverticulitis. This includes limiting red meat to less than four servings a week, increasing fiber to more than 23 g daily, exercising vigorously for more than two hours per week, maintaining body mass index at 18.5-24.9 kg/m2 and not smoking. Each component lowers the risk significantly, and each should be recommended to patients.
“We have to have that fairly detailed discussion to tell [patients] they can do something about this condition,” he emphasized.
One important thing patients can do is increase their fiber intake. Dr. Stollman said an inverse relationship exists between fiber intake and clinically evident diverticular disease, as demonstrated in at least two large prospective cohort studies showing that the risk for symptomatic disease (i.e., diagnosis of diverticulitis or hospitalization) was reduced by approximately 40% in the highest versus the lowest quartiles of fiber intake (J Nutr 1998;128[4]:714-719; BMJ 2011;343:d4131). In addition, according to 1 million person-years of long-term data from the Health Professionals Follow-up Study (HPFS), individuals in the top quintile consuming the unhealthy “Western” diet had a 72% increased risk compared with the lowest quintile consuming the “prudent” diet (Gastroenterology 2017;152[5]:1023-1030).
Importantly, the study demonstrated that more recent dietary intake was a greater influence on risk than past intake, Dr. Stollman noted, dispelling the myth that changes in the diet won’t affect existing diverticulosis. “That takes away some of the nihilism I think we sometimes feel with diverticulosis, suggesting that, in fact, you can do something about it,” by consuming a fiber-rich diet, he commented.
Another stubborn myth that persists is that nuts and seeds should be off-limits for patients with a history of acute diverticulitis. “There’s literally no data in support of this,” Dr. Stollman said. In fact, an 18-year follow-up of the HPFS published in 2008 found that consumption of nuts and popcorn was associated with a significantly reduced risk (JAMA 2008;300[8]:907-914). “We shouldn’t be telling our patients not to eat seeds or nuts or popcorn—the science and the published guidelines back that up,” he said.
“We rarely talk about physical activity and diverticular disease, but there are some data, again from the HPFS, suggesting that patients with a high level of activity have a 34% lower risk of acute diverticulitis,” Dr. Stollman explained (Am J Gastroenterol 2009;104[5]:1221-1230). “I wouldn’t have been telling patients about the importance of exercise 10 years ago, but I think it’s important to tell them now.”
Role of Medications
Nonsteroidal anti-inflammatory drugs (NSAIDs) are clearly the most significant risk factor for diverticular bleeding. In a recent meta-analysis of 13 studies, regular use of these drugs increased the risk for diverticular bleeding almost sevenfold, and tripled the risk for complicated recurrence. Aspirin use increased the risks approximately two- and threefold, respectively (Int J Colorectal Dis 2022;37[3]:521-529).
Because of this evidence, Dr. Stollman suggested that elective use of NSAIDs—not including aspirin when it is indicated—be avoided or minimized in all patients with a history of diverticulitis.
Genetic Factors
Another development in the understanding of diverticular disease is the involvement of genetics. “We’ve long thought of diverticular disease as an acquired disorder, but could there be a genetic predisposition as well? Contrary to what has long been believed, there almost certainly is,” he said. The estimated heritability was determined to be 40% in the Swedish Twin Registry and 53% in the Danish Registry (Aliment Pharmacol Ther 2012;35[9]:1103-1107; Gastroenterology 2013;144[4]:736-742).
Single-nucleotide polymorphisms in the TNFSF15 and LAMA4 genes have been shown to be associated with the condition, albeit not necessarily causally.
Posture During Defecation
A novel prospective comparative study from Turkey, where people sometimes squat to defecate rather than sit on Western-type toilets, has concluded that sitting during defecation increases the risk for diverticulosis. The study involved 757 persons undergoing colonoscopy, of whom 12% were diagnosed with diverticulosis. The investigators found that 72% of those with diverticulosis reported sitting compared with 53% of those without diverticulosis (P=0.007) (Acta Gastroenterol Belg 2018;81[4]:490-495).
“Sitters—and the longer they sat—had a higher risk of diverticular disease than people who basically squatted,” Dr. Stollman said. “That angle is better for defecation.”
Dr. Stollman noted that a hot seller on the television series “Shark Tank” is a product that answers the need this study addresses: The Squatty Potty, which, as the promotion reads, “is engineered to mirror the angle and efficiency of natural squatting, while allowing for the luxury and comfort of your own toilet.”
Treatment of Acute Diverticulitis
Dr. Stollman also discussed some considerations for managing patients with acute disease, such as use of antibiotics and other therapies, as well as surgery.
“Who says we should use antibiotics for acute diverticulitis? Everyone,” Dr. Stollman said. “In all the currently recommended protocols, the only discussion point in any of them is maybe which antibiotic to use and maybe inpatient versus outpatient care,” he said.
| Table. AGA Diverticular Disease Recommendations The AGA guidance on diverticular disease includes the following suggestions and recommendations. | |
| AGA suggestions | Quality of evidence |
|---|---|
| For advising a fiber-rich diet or fiber supplementation in patients with a history of acute diverticulitis | Conditional recommendation; very low quality of evidence |
| Against routinely advising patients with a history of acute diverticulitis to avoid consumption of nuts and popcorn | Conditional recommendation; very low quality of evidence |
| For advising patients with diverticular disease to consider vigorous physical activity | Conditional recommendation; very low quality of evidence |
| For advising patients with a history of diverticulitis to avoid non-aspirin nonsteroidal anti-inflammatory drugs if possible | Conditional recommendation; very low quality of evidence |
| Against the use of rifaximin after acute uncomplicated diverticulitis | Conditional recommendation; very low quality of evidence |
| Against elective colonic resection in patients with an initial episode of acute uncomplicated diverticulitis. The decision to perform elective prophylactic colonic resection in this setting should be individualized. | Conditional recommendation; very low quality of evidence |
| AGA recommendation | Quality of evidence |
| Against the use of mesalamine after acute uncomplicated diverticulitis | Strong recommendation; moderate quality of evidence |
| AGA, American Gastroenterological Association. Based on Gastroenterology 2015;149(7):1944-1949. | |
But with inappropriate antibiotic usage a pressing concern, the better question is whether some patients can safely avoid them, Dr. Stollman noted. Multiple large randomized trials, including a meta-analysis, have found no significant difference between patients who received antibiotic treatment and those who did not with respect to outcomes including time to recovery, complicated diverticulitis, recurrent diverticulitis, surgery, readmissions, adverse events and mortality (Am J Surg 2018;216[3]:604-609).
For uncomplicated disease, “I usually give the patient a prescription, probably for [amoxicillin and clavulanate], and tell the patient: ‘Go home, take some [acetaminophen], but hold off on the antibiotic and see how you do. If you’re worse tomorrow, then take it,’” said Dr. Stollman. “The science is clear, and you are not going to get into trouble for doing this.”
With respect to other medical therapies, there is no strong evidence to support the use of mesalamine, rifaximin or other probiotics after acute diverticulitis, and these interventions are not routinely recommended, although they may be tried in certain challenging patients, Dr. Stollman noted.
Reviewing the appropriate uses of surgery, Dr. Stollman said that the available data show that elective colonic resection should be discouraged after an initial episode of diverticular disease but that it is reasonable to consider after a third or fourth episode. He said surgery also can be considered for a young patient with aggressive disease—especially segmental disease confined to the sigmoid colon, which is a relatively simpler and less morbid operation.
—Caroline Helwick
This article is from the February 2023 print issue.