ACP Advocates Outpatient Treatment of Uncomplicated Diverticulitis

Heidi Splete

January 19, 2022

A pair of updated clinical guidelines from the American College of Physicians on the diagnosis and management of diverticulitis emphasized reduced use of antibiotics, outpatient management, and informed decision-making prior to elective surgery.

The estimated prevalence of acute colonic diverticulitis in the United States appears to be on the rise, wrote Amir Qaseem, MD, and members of the ACP Clinical Guidelines Committee. "Approximately 200,000 hospitalizations for acute left-sided colonic diverticulitis occur in the United States each year, with annual costs of more than $8 billion. Timely and correct diagnosis of acute left-sided colonic diverticulitis is essential for the selection of the most appropriate management options."

Diverticulitis is becoming increasingly common in patients treated by internal medicine physicians, according to the ACP, and the new clinical guidelines specify a course of treatment focused on outpatient management and minimal medications.

The guidelines, published in Annals of Internal Medicine, were based on a systematic review of evidence from studies published between Jan. 1, 1990, and June 1, 2020. Notably, right-sided diverticulitis was excluded because it is rare in Western countries and involves a different natural history and management options, the authors wrote.

In the guidelines, uncomplicated diverticulitis refers to localized inflammation, and complicated diverticulitis refers to "inflammation associated with an abscess, a phlegmon, a fistula, an obstruction, bleeding, or perforation."

Guidance on Diagnosis and Management

In the first guideline, "Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis", the authors provided three recommendations. First, they recommended that clinicians use abdominal CT imaging in cases of diagnostic uncertainty for patients with suspected acute left-sided colonic diverticulitis. The evidence showed that abdominal CT was associated with appropriate management in patients with suspected acute left-sided colonic diverticulitis, and that misdiagnosis with CT was rare.

Second, the authors of this guidance recommended management of most patients with acute left-sided colonic diverticulitis in an outpatient setting. Evidence showed that the risk for elective surgery and for recurrence were not significantly different based on inpatient or outpatient management.

The third recommendation advised clinicians to manage most patients without antibiotics. This recommendation was based on data showing no significant difference in quality of life at 3, 6, 12, or 24 months; no difference in diverticulitis-related complications; and no difference in the need for surgery in patients treated with antibiotics and those not treated with antibiotics.

All three recommendations are conditional, with low-certainty evidence, according to the authors.

Colonoscopy for Diagnostic Evaluation and Interventions

In the second guideline, "Colonoscopy for Diagnostic Evaluation and Interventions to Prevent Recurrence After Acute Left-Sided Colonic Diverticulitis, the authors advised clinicians to refer patients for a colonoscopy after an initial episode of complicated left-sided colonic diverticulitis if they have not had a recent colonoscopy.

Although acute diverticulitis is usually uncomplicated, approximately 12% of cases are considered complicated, and these patients may have a higher prevalence of colorectal cancer, the authors noted. This recommendation was conditional, with low-certainty evidence. Additional diagnostic colonoscopy is not needed for patients who are up to date on recommended colorectal cancer screening, according to this guideline.

A second recommendation, given as a strong recommendation with high-certainty evidence, advised against using mesalamine to prevent recurrent diverticulitis. Evidence showed that use of mesalamine at doses ranging from 1.2 g/day to 4.8 g/day made no difference in recurrent diverticulitis risk compared with placebo. Mesalamine has no demonstrated clinical benefits, and has been associated with epigastric pain, nausea, diarrhea, dizziness, rash, and renal and hepatic impairment, the authors wrote.

The third recommendation advised the discussion of elective surgery with patients with a history of uncomplicated diverticulitis that persists or recurs frequently. Surgery also may be an option for patients with complicated diverticulitis, according to the guideline. However, "this recommendation does not apply to patients with uncomplicated diverticulitis that is not persistent or frequently recurring," the authors wrote.

The decision to pursue elective surgery should be informed and personalized according to potential benefits, harms, costs, and patient preferences, they said. This recommendation is conditional, with low-certainty evidence.

This new guideline was designed "to guide care based on the best available evidence and may not apply to all patients or individual clinical situations," the authors emphasized. "It should not be used as a replacement for a clinician's judgment."

Update Confirms Best Practices

"Concerns about inappropriate antimicrobial therapy use and the delay in seeking preventative care such as a colonoscopy have led to poorer outcomes for patients," ACP president George Abraham, MD, said in an interview. These concerns about a lack of antimicrobial stewardship and of care not being representative of 'high value care' "supported the need to reinforce best practices."

Although most clinicians are aware of the nature of the recommendations in their own clinical practices, "a systematic review helped confirm and codify best practice that everyone can confidently incorporate into their daily decision-making," Abraham said.

Compared with previous guidelines, "the single biggest difference is the fact that antimicrobial therapy is not indicated in mild, uncomplicated diverticulitis; we hope this will lead to lesser and more judicious antimicrobial prescribing," Abraham emphasized.

Like all guidelines, the current guidelines are meant to be advisory, not mandatory; "they do not replace good clinical judgment and individual patient care decision-making," Abraham said. "These guidelines are useful when they are widely read by clinicians, including physicians and advanced practice clinicians, and incorporated into their daily practice."

Curbing Antibiotic Use

It is important for clinicians to recognize that uncomplicated diverticulitis in selected patients does not require initial antibiotics, David A. Johnson, MD, chief of gastroenterology at Eastern Virginia School of Medicine, Norfolk, said in an interview. "This paradigm shift began with the AGA guidelines in 2015, and was more recently updated with the 2021 best practice recommendations," first published in Gastroenterology.

"I was surprised to see this current guideline not mentioning that, if antibiotics are to be used, that amoxicillin-clavulanate alone should be favored over combination of fluoroquinolones and metronidazole," Johnson noted. "Furthermore, the U.S. Food and Drug Administration has advised that fluoroquinolones should be reserved for conditions with no alternative treatment options."

"The initial management approach for the AGA guidelines and best practice are comparable with these most recent ACP recommendations," said Johnson. However, "I would suggest that clinicians treating diverticulitis also review the AGA best practice recommendations, which build out important other important points for diverticulitis management including timeframes for colonoscopy, strong effect of genetics, dietary effects, recurrence rates, and the role of surgery."

As for research gaps, "further data on cost savings would be helpful," as savings may be likely with significant reduction without antibiotics and imaging in select patients, Johnson said. "Cost savings and risk reduction of adverse implications of antibiotic and radiation risks should be included in these analyses."

The guidelines were based on systematic reviews conducted by the Evidence-based Practice Center at Brown University, Providence, R.I., funded by the Agency for Healthcare Research and Quality. The development of the guidelines was supported by the ACP operating budget. The authors, Abraham, and Johnson had no financial conflicts to disclose.

This article originally appeared on, part of the Medscape Professional Network.


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