Evid Based Med 18:32-33 doi:10.1136/eb-2012-100762
  • Therapeutics
  • Randomised controlled trial

Antibiotics may not improve short-term or long-term outcomes in acute uncomplicated diverticulitis

  1. Tim W Eglinton2
  1. 1Department of Surgery, Christchurch Hospital, Christchurch, New Zealand
  2. 2Department of Surgery, University of Otago, Christchurch, New Zealand
  1. Correspondence to: Tim W Eglinton
    Department of Surgery, University of Otago, Christchurch 8140, New Zealand; tim.eglinton{at}

Commentary on: [CrossRef][Medline]Google Scholar


Diverticular disease affects one in three people over the age of 60 years in Western countries and up to a quarter of these patients will develop diverticulitis.1 ,2 Acute uncomplicated diverticulitis typically presents with localised abdominal pain, fever and raised inflammatory markers. The current standard of care is antibiotic treatment, although evidence supporting this recommendation is lacking.1 This study evaluates whether or not antibiotic therapy for acute uncomplicated left-sided diverticulitis improves recovery.


A non-blinded randomised clinical trial comparing treatment of acute uncomplicated left-sided diverticulitis with or without antibiotics was performed. Adult patients were enrolled if they had a history and clinical signs of acute diverticulitis, a raised white cell count (WCC) and C-reactive protein (CRP) and a corroborating CT scan. Patients were excluded if they had radiological evidence of complicated diverticulitis (abscess, free gas or fistula) or were taking immunosuppressive medication. Patients were randomised to receive either intravenous fluids alone (309 patients) or in combination with broad-spectrum antibiotics (314 patients). Intravenous antibiotics were initiated and then converted to oral antibiotics with a total duration of antibiotic therapy of at least 7 days. Patients in both groups were discharged when apyrexial with resolving abdominal pain/tenderness and an improving WCC and CRP. This multicentre study was conducted between October 2003 and January 2010 in 10 surgical departments in Sweden and 1 in Iceland and used centre-stratified block-permuted randomisation. The primary outcome was recurrence of symptomatic diverticulitis requiring readmission to hospital within 12 months of the sentinel episode. Complications, operations and duration of hospital stay were also compared between the two groups. All statistical tests were two-sided, with p<0.05 considered significant.


Of 623 trial participants, 41 were lost to follow-up. In the remaining 582 patients, the rate of recurrent diverticulitis necessitating hospital readmission at 12 month follow-up was similar between the two groups (16%, p=0.881). The median duration of hospital stay was 3 days in both groups. The rate of complications (sigmoid perforation or abscess formation) in patients who received no antibiotics was similar to that in patients who were treated with antibiotics (1.9% vs 1.0%, p=0.302). There was no significant difference in the rate of sigmoid resections (during the index episode or at 12 month follow-up) between the two groups.


Chabok and colleagues report that antibiotics in acute uncomplicated diverticulitis do not shorten hospital stay, prevent complications or reduce recurrence. This is the first randomised clinical trial to investigate the need for antibiotic treatment in acute uncomplicated diverticulitis and supports the conclusions of two earlier retrospective studies which suggested that antibiotics were not beneficial.3 ,4

The use of antibiotics to treat diverticulitis is based on the longstanding premise that it is caused by colonic microperforation.5 However, recently, it has been proposed that diverticulitis represents a form of inflammatory bowel disease and limited data suggests that mesalazine may be effective in preventing recurrent attacks.6 Establishing the aetiology of inflammation in diverticulitis will be an important step in determining the most appropriate therapeutic strategy.

Consistent with previous studies examining the natural history of diverticulitis, this study found a significant positive relationship between previous episodes of diverticulitis and recurrence.7 Since there were significantly fewer patients with a previous history of diverticulitis in the antibiotic treatment group, the results regarding recurrence may be biased towards this arm of the trial. Future studies should use stratified randomisation to control for this variable.

Overall, this is a well-performed study. However, the exclusion of patients with ‘sepsis’, the large differences in recruitment between participating centres and the very low overall rate of complications (1.4%) suggest selection bias towards mild uncomplicated diverticulitis. Further studies are required to refine the patient population in whom antibiotics can be safely withheld. The potential benefits of withholding antibiotic treatment include shorter hospital stays, lower costs, reduced development of bacterial resistance to antibiotics and fewer side-effects.


  • Competing interests None.


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