Surgeons Tackle Pressing Questions on Diverticulitis Management

Originally published by our sister publication General Surgery News

As the third most common gastrointestinal disease in the United States, diverticular disease is an everyday part of practice for general surgeons. But that doesn’t mean its treatment is simple or straightforward. At the 2024 Clinical Congress of the American College of Surgeons, experts discussed quality-of-life issues, challenging populations, and what to say when your patients ask about the power of probiotics.

Does Surgery Improve Quality of Life?

The goals of elective surgery for diverticulitis have changed, said Emily Steinhagen, MD, an associate professor of surgery at Case Western University School of Medicine, in Cleveland.

“We used to say that an important goal of elective surgery was to prevent severe attacks requiring a stoma. We now want to prevent future attacks and hospitalizations and to cure symptoms.”

Colectomy can offer a more than 90% rate of cure, but there are comorbid risks that come with it. Current guidelines prioritize not having strict recommendations for elective surgery. Instead, they focus on quality of life (QOL) and generally support personalized treatment, Dr. Steinhagen said.

“However, individualizing surgical choices presents a unique challenge when there is more than one treatment option,” she noted. The surgeon may be an expert in the health condition and treatments, but the patient is an expert in what matters most to them. “Patients may think surgery is the only fix, or they may see it as prohibitively risky regardless of their personal risk.”

The number of studies on how diverticular disease affects QOL are not numerous, “but they do constitute good evidence, taken all together, that can help us when we’re thinking about how to counsel patients and discuss options,” Dr. Steinhagen said.

A 2009 survey of patients who underwent surgery found that about half of them experienced a significant improvement in QOL measures starting three months after surgery and onward (Ann Surg 2009;249[2]:218-224). A larger study with a longer follow-up had similar results, with nearly all patients saying they would have surgery again (Int Colorectal Dis 2012;27[6]:781-787), and a meta-analysis also found significant improvements in QOL (Scand J Gastroenterol 2024;59[7]:770-780).

“This brings us to two randomized controlled trials,” Dr. Steinhagen said.

The DIRECT trial compared conservative and surgical treatments with a primary end point of change in QOL (Ann Surg 2019;269[4]:612-620). The mean difference in QOL after surgery was 9.7, slightly short of the score of 10 considered clinically significant, but an improvement of 10 points was seen in two-thirds of patients in the operative group and in 57% of those in the conservative group. Of note, patients in the conservative group who experienced recurrent attacks were offered surgery, and 14 of 26 patients accepted.

“So, though this is an intention-to-treat analysis, it probably significantly underestimates the effect because the subgroup assigned to conservative management who then underwent surgery had a QOL improvement of more than 20 points,” Dr. Steinhagen said.

The LASER trial was stopped early due to positive results, with scores on QOL improving 11.8 points and a complication rate of about 10% (JAMA Surg 2023;158[6]:593-601).

However, it is important to note that in both those RCTs, although many patients experienced improvement, there were some who did not. When Dr. Steinhagen counsels patients, she thinks about best case, worst case and most likely case, and refers to a 2007 study that surveyed patients about 40 months after their surgery.

More than half of these patients, 57%, reported better bowel function after surgery; 7% reported worse; and 37% reported no change. Overall, most patients reported being satisfied with their outcomes (J Gastrointest Surg 2007;11[6]:767-772).

So, does surgery improve QOL in patients with diverticular disease? “The data suggests it does, particularly for patients whose QOL is decreased by their symptoms and who don’t have other causes of GI dysfunction.

“But the key is to have realistic expectations and to partner with our patients in true shared decision-making,” Dr. Steinhagen said.

The Immunocompromised Patient

With increasing numbers of organ transplant patients and better immunosuppressive agents, surgeons are seeing many more immunocompromised patients among their diverticular disease population. In 2020, the American Society of Colon and Rectal Surgeons (ASCRS) revised its guidelines to recommend individualizing surgery for these patients, said Nitin Mishra, MD, an associate professor at Mayo Clinic in Phoenix.

But questions remain about how well they do and whether they should be treated differently from non-immunocompromised patients. When Dr. Mishra was a program director at Mayo, Shengliang He, MD, a resident, suggested that since their clinic does more transplants than any other, they should research the management of diverticular disease in immunocompromised patients.

“We included immunocompromised patients from all three sites: 74 transplant patients, 25 with rheumatologic disease, nine cancer patients and 14 in other categories.”

The 86 patients with uncomplicated disease were managed medically; two failed medical treatment and four were readmitted within a month. “If you think about your own practice and you have 86 patients—forget the immunocompromised part—two fail and four bounce back, this is essentially the natural history of diverticulitis,” Dr. Mishra said.

Patients with perforations went straight to the OR, “which is what we would do with any patient with perforated diverticulitis,” he said.

There were 22 patients with abscesses. Those with small abscesses were managed medically and those with large abscesses received an interventional radiology (IR) tube for drainage.

“Based on these results, we concluded that nonoperative management is safe for immunocompromised patients without perforation or obstruction. If they have a perforation, they should get surgery up front,” Dr. Mishra said (Dis Colon Rectum 2023;66[3]:434-443).

It’s important to note that immunosuppressed patients are not all the same. Some are immunosuppressed because of intrinsic reasons—something the patient has, like AIDS—whereas others are related to treatments, such as steroids, chemotherapy and post-transplant agents, and duration can vary from temporary to permanent. All these variables can affect how patients present with diverticulitis.

As examples, two papers found that patients on opiates and corticosteroids “tend to perforate more than patients immunosuppressed by any other means,” Dr. Mishra said (Am J Surg 2016;212[3]:384-390 and Gut 2011;60[2]:219-224).

“If someone is on corticosteroids, their rate of [disease] recurrence tends to be high. Like most immunosuppressed patients, they tend to mask their symptoms and may present late, and they tend to perforate more. When the immunosuppression is corticosteroid-based, you should have a lower threshold to intervene,” Dr. Mishra said.

When it comes to surgical intervention, the common options are Hartmann’s, resection and primary anastomosis (RPA), and RPA and diversion. Research has supported RPA as emergency surgery in immunocompromised diverticulitis patients (Colorectal Dis 2014;16[9]:723-731), but Dr. Mishra mentioned some considerations.

“I know the needle is moving in that direction, but consider the physical toll of an ileostomy in an immunocompromised patient. If you think they won’t be able to tolerate an ileostomy, do a Hartmann’s and get that reversed at some point,” he said.

To summarize, immunocompromised patients with uncomplicated diverticulitis are treated like non-immunocompromised patients. Those with a perforation are sent to surgery unless they are not candidates, in which case they’re sent to hospice. Patients with an obstruction are sent to surgery even if they are not candidates for colectomy.

“At the very least, they need something venting. It is not a kind thing to let someone die of an obstruction—we don’t send them to hospice without surgery,” Dr. Mishra pointed out.

The Gut Microbiome And Diverticulitis

In the past 10 to 15 years, research has shown that diet influences the composition and function of the gut microbiome, leading investigators to hypothesize that this factor could, via the microbiome, be a driver of diverticulitis.

“Is this theory or is there evidence for this? The evidence is very associative,” said Ben Shogan, MD, an associate professor of surgery at the University of Chicago.

In a 2017 study comparing patients with symptomatic or asymptomatic, uncomplicated diverticulitis and healthy controls, researchers found differing composition of bacteria in the subjects’ feces (Gut 2017;66[7]:1252-1261).

“When they looked at the types of taxa that were present, they found that bacterial groups that were decreased in those with diverticular disease encompassed multiple anti-inflammatory species, a similar phenotype as is seen in [inflammatory bowel disease] or [irritable bowel syndrome],” Dr. Shogan said.

The researchers found a similar pattern in the macrophages within the wall of the diverticulum, “again suggesting that the microbes in patients who developed diverticulitis are pro-inflammatory.”

Based on that study and others published around the same time with similar findings, Dr. Shogan came to the conclusion that patients with a history of uncomplicated diverticulitis have decreased short-chain fatty acid–producing bacteria, decreased anti-inflammatory bacteria and increased mucin-degrading bacteria.

What about complicated diverticulitis? A study of 65 patients, 44 of whom had uncomplicated diverticulitis, 21 had complicated diverticulitis and 25 healthy controls found that the fecal swabs of those with acute diverticulitis differed not only from controls, but from uncomplicated diverticulitis patients (Colorectal Dis 2022;24[12]:1591-1601).

“And again, the patients with complicated diverticulitis had increased inflammatory taxa,” Dr. Shogan said.

Later studies showed similar patterns, with one finding increased bacteria associated with intestinal permeability, mucin degradation and sulfur production in patients with perforated, complicated diverticulitis (Dis Colon Rectum 2023;66[5]:707-715). Another investigation, based on a much larger study, was able to control for variables such as age, race, Bristol score, antibiotic use and fiber intake—all of which cause differences in the microbiome—found pro-inflammatory taxa in subjects with a history of diverticulitis (Nat Commun 2024;15[1]:3612). Finally, a meta-analysis of 12 studies reported bacterial differences in subjects with diverticulitis, although its conclusion did not support microbial dysbiosis as a contributing factor in diverticulitis (J Gastroenterol Hepatol 2023;38[7]:1028-1039). “But if you look at [the] discussion, the studies were very dissimilar to each other, making it challenging to draw any solid conclusions,” Dr. Shogan said.

“So, is this unsolved mystery solved? I don’t think so. The data suggests a high association between changes in the microbiome that make theoretical sense, but is this cause or consequence?” Dr. Shogan said, noting that the absence of animal models for studying the microbiome limits the possibilities for research.

But it’s almost inevitable that patients will ask about probiotics. Could ingesting gut health–promoting live bacterial strains help prevent attacks of diverticulitis?

“I would say, maybe. There have been a handful of investigations, some with positive results and some with negative results. These studies are of relatively poor quality; each has different treatments; the patients are very heterogeneous; and the studies all have very different outcomes,” Dr. Shogan said, noting that this is why ASCRS states that probiotics are typically not recommended to reduce the risk for diverticulitis based on grade 2B evidence.

What can you do? “If someone comes in with a perforated colon, they’re getting antibiotics, surgery and an IR drain. But those with uncomplicated diverticulitis and no abscess or perforation?” Dr. Shogun asked. Based on recent studies, the ASCRS recommends avoiding antibiotics in selected patients with uncomplicated diverticulitis. “It’s important to realize that they do say ‘selected patients’—those who are really not that sick by the inflammatory response they’re experiencing at that time or by comorbidities.

“But I think we all agree that antibiotics should be indicated in all other cases: uncomplicated diverticulitis in patients with comorbidities and in complicated diverticulitis,” Dr. Shogan said.