Skip Antibiotics in Uncomplicated Diverticulitis, RCT Shows

Troy Brown, RN

October 07, 2016

In patients with a first episode of uncomplicated diverticulitis, antibiotics did not improve outcomes, according to the results of a randomized controlled trial (RCT). The authors conclude patients with Hinchey stages 1a diverticulitis can be treated with observation alone.

The median time to recovery during 6 months of follow-up, which was the primary endpoint, was 14 days (interquartile range, 6 - 35 days) for patients in the observational treatment group compared with 12 days (interquartile range, 7 - 30 days) among those who received antibiotic treatment. Compared with antibiotic treatment, an observational approach was associated with a hazard ratio for full recovery of 0.91 (lower limit of one-sided 95% confidence interval, 0.78; P = .151).

"Treatment without antibiotics is controversial, as guidelines have remained unchanged despite evidence from two observational studies and one [randomized controlled trial (RCT)] indicating that antibiotics have no benefit," the researchers write. "The previous RCT evaluated 623 patients, but some drawbacks of its methodological design may account for the lack of change in clinical practice."

Lidewine Daniels, MD, from the Department of Surgery, Academic Medical Centre, University of Amsterdam, the Netherlands, and colleagues from the Dutch Diverticular Disease Collaborative Study Group report their findings in an article published online September 30 in the British Journal of Surgery.

The current trial, called Diverticulitis: Antibiotics or Close Observation, or DIABOLO, was a multicenter, open-label, pragmatic, RCT of two accepted treatment strategies. The study included 528 patients with a first episode of left-sided, uncomplicated (modified Hinchey stages 1a-b and Ambrosetti's 'mild' diverticulitis stage), acute diverticulitis.

Of those, 266 patients received antibiotic treatment according to the practice guidelines of the Dutch Antibiotic Policy Committee and the American Society of Colon and Rectal Surgeons. Patients received a 10-day course of amoxicillin-clavulanic acid, beginning with 1200 mg intravenously four times daily for at least 48 hours, after which they could be switched to 625 mg orally three times daily, if tolerated. Patients who were allergic switched to the combination of ciprofloxacin and metronidazole. All patients in the antibiotic group were admitted to the hospital for intravenous antibiotic administration.

In the observation group, 262 patients received treatment in an outpatient setting once they met the following criteria: toleration of a normal diet, temperature lower than 38°pain score measured on a visual analogue scale lower than 4 with nothing stronger than paracetamol for pain, capable of the same level of self-support as before their illness, and patient acceptance.

Patients visited the outpatient clinic at 2 and 6 months and followed up by telephone at 12 and 24 months.

The median duration of initial hospital stay was shorter in the observation group as a result of the intravenous administration of antibiotics in the antibiotic group (2 vs 3 days; P = .006).

Other secondary outcomes did not differ significantly between the groups during 6 months' follow-up. Complicated diverticulitis rates were 3.8% in the observation vs 2.6% in the antibiotic group (P = .377). Ongoing diverticulitis occurred in 19 patients (7.3%) in the observation group compared with 11 (4.1%) in the antibiotic group.

The proportion of patients who experienced recurrent diverticulitis was similar in the observation group compared with the antibiotic group (3.4% vs 3.0%; P = .494).

Sigmoid resection rates were similar (3.8% vs 2.3%; P = .323) for both emergency (0.8% vs 1.1%; P = .553) and elective (3.1% vs 1.1%; P = .254) resection. The most common reasons for sigmoid resection were colonic obstruction (3 of 10 patients in the observation group and 2 of 6 in the antibiotic group) and perforation (2 of 10 patients in the observation group and 2 of 6 patients in the antibiotic group).

There were no significant differences in the occurrence of mild (P = .086) or serious (P = .354) adverse events, although antibiotic-related adverse events occurred more frequently in the antibiotic group (0.4% in the observation group vs 8.3% in the antibiotic group; P = .006). All but one antibiotic-related adverse events were mild. Mortality rates did not differ between the groups (1.1% vs 0.4%; P = .432).

The researchers caution that antibiotics should be withheld only in patients with Hinchey 1a diverticulitis until larger studies have been conducted.

"There are no other reports on observational versus antibiotic management of Hinchey 1b disease. Omitting antibiotics in the treatment of uncomplicated acute diverticulitis should be limited to Hinchey 1a until larger Hinchey 1b samples have been examined," the authors explain. "Moreover, recommendations for patients with significant co-morbidity or inflammatory bowel disease, and those who are pregnant or immunocompromised, cannot be made based on the present results. Patients with body temperature exceeding 39̊°C, sepsis and/or positive blood cultures warrant antibiotic treatment," they conclude.

The authors have disclosed no relevant financial relationships.

Br J Surgery. Published online September 30. Abstract

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