We have had patients with a straightforward diagnosis of uncomplicated acute sigmoid diverticulitis confirmed by CT whose dispositions, unfortunately, were not as clear-cut. Many have drug allergies from A (ampicillin) to Z (Zithromax), with a C (ciprofloxacin), an M (metronidazole), and others in between.
One theory—that diverticulitis is less about infection and more about inflammation—may mean that antibiotics aren't always necessary. What does the evidence say about the risks and benefits of this management?
The STAND (Selective Treatment with Antibiotics for Non-Complicated Diverticulitis) double-blind non-inferiority trial from Jaung, et al., compared placebo with antibiotic treatment for managing uncomplicated acute diverticulitis in New Zealand and Australia. (Clin Gastroenterol Hepatol. 2020;S1542-356530426.) The study included 180 patients hospitalized for uncomplicated acute diverticulitis (Hinchey 1a grade on CT, which means no free air, abscess, or fistula) who were randomly assigned to receive antibiotics (n=85) or placebo (n=95).
The standard regimen was oral Augmentin 625 TID for the whole seven-day course. Physicians had the option to replace the opening day or two of Augmentin with an intravenous-based starter regimen: cefuroxime 750 mg Q six hours combined with oral metronidazole 400 mg TID. Five percent of the placebo group received at least one dose of an antibiotic prior to enrollment. The authors compared length of hospital stay (their primary outcome), adverse events, readmission to the hospital, procedural intervention, change in serum markers of inflammation, and patient-reported pain scores at 12 and 24 hours.
They found similar outcomes between groups in median hospital length of stay (40 for the antibiotic group v. 46 hours for placebo), adverse events (12% v. 12%), mean decrease in WBC (2.9 v. 2.7), and pain score at 24 hours (3.0 v. 3.2). There was a signal toward increased 30-day serious adverse events (n=3 v. 0) and procedural intervention (n=2 v. 0) in the antibiotic group, but the trial design was not powered to allow for meaningful conclusions about these secondary outcomes. With this caveat, the trial was pretty tightly run with minimal protocol disruptions.
Only three participants were lost to follow-up. And these study results are consistent with existing evidence on this question from other settings. (Scand J Gastroenterol. 2007;42:41.) Daniels, et al., randomized 528 Dutch patients with acute uncomplicated diverticulitis to observation or antibiotics, and found no significant differences in median time to recovery (14 days v. 12 days) or in secondary six-month outcomes (after adjustment for multiple comparisons): complicated diverticulitis (3.8% v. 2.6%), recurrent diverticulitis (3.4% v. 3.0%), sigmoid resection (3.8% v. 2.3%), readmission (17.6% v. 12.0%), adverse events (48.5% v. 54.5%), or mortality (1.1% v. 0.4 %). (Br J Surg. 2017;104:52.)
The evidence would seem to imply that a subset of acute diverticulitis patients can do well without antibiotics, but there is certainly no international consensus on the specifics or safety of an antibiotic-free management strategy. A 2014 Delphi international consensus effort involving experts from Australasia, Asia, Europe, and North America, for example, resulted in this clear-as-mud conclusion: “Controversy continues internationally regarding the management of acute diverticulitis. This study demonstrates that there is more nonconsensus among experts than consensus regarding most issues, even in the same region.” (JAMA Surg. 2015;150:899; https://bit.ly/2GSrIOI.)
The only regions to come to a consensus yes were the United States and Australasia. On the other hand, the American Academy of Family Physicians has endorsed the concept that bug juice is not needed for all cases of acute diverticulitis. (Am Fam Physician. 2013;87:612; https://bit.ly/3nNo3m0.) And the American Society of Colon and Rectal Surgeons, which used to disagree, is now in alignment. (Dis Colon Rectum. 2020;63:728; https://bit.ly/2GT4DLP.) Perhaps this new study from Jaung, et al., will be enough to gently push the needle on practice change in the ED.
Antibiotic-averse patients will likely be happy to trade away the known aggravation of medication side effects for the small (but unknown) risk of forgoing antibiotic therapy for what proves to be an inflammatory condition. We know this is an unconventional approach, but can be supported with close follow-up by the patient's primary care physician. Many do well at home with analgesics, and their diverticulitis resolves without short-term recurrence.
This antibiotic-free approach to acute diverticulitis can be an attractive option. We look forward to trying it in a patient without allergies. The downside is that the eligibility criteria require CT imaging, which is not risk-free. We imagine one day having a protocol in place where select low-risk patients with presumed acute diverticulitis could be treated without imaging, antibiotics, or hospitalization. This would, of course, require multispecialty buy-in with timely follow-up.
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Dr. Vinsonis an emergency physician at Kaiser Permanente Sacramento Medical Center, a chair of the KP CREST (Clinical Research on Emergency Services and Treatment) Network, and an adjunct investigator at the Kaiser Permanente Division of Research (https://www.kpcrest.net/). Dr. Ballardis an emergency physician at San Rafael Kaiser, a past chair of the KP CREST Network, and the medical director for Marin County Emergency Medical Services. Read their past articles athttp://bit.ly/EMN-MedClear.
Podcast: Physician Gestalt
Listen to a podcast where Gita Pensa, MD, interviews Dr. Ballard about physician gestalt in estimating the probability of acute appendicitis in children: https://bit.ly/37k0jA7.