Randomized clinical trial of observational versus antibiotic treatment for a first episode of CT-proven uncomplicated acute diverticulitis

Background: Antibiotics are advised in most guidelines on acute diverticulitis, despite a lack of evidence to support their routine use. This trial compared the effectiveness of a strategy with or without antibiotics for a first episode of uncomplicated acute diverticulitis. Methods: Patients with CT-proven, primary, left-sided, uncomplicated, acute diverticulitis were included at 22 clinical sites in the Netherlands, and assigned randomly to an observational or antibiotic treatment strategy. The primary endpoint was time to recovery during 6 months of follow-up. Main secondary endpoints were readmission rate, complicated, ongoing and recurrent diverticulitis, sigmoid resection and mortality. Intention-to-treat and per-protocol analyses were done. Results: A total of 528 patients were included. Median time to recovery was 14 (i.q.r. 6-35) days for the observational and 12 (7-30) days for the antibiotic treatment strategy, with a hazard ratio for recovery of 0.91 (lower limit of 1-sided 95 per cent c.i. 0.78; P = 0.151). No significant differences between the observation and antibiotic treatment groups were found for secondary endpoints: complicated diverticulitis (3.8 versus 2.6 per cent respectively; P = 0.377), ongoing diverticulitis (7.3 versus 4.1 per cent; P = 0.183), recurrent diverticulitis (3.4 versus 3.0 per cent; P = 0.494), sigmoid resection (3.8 versus 2.3 per cent; P = 0.323), readmission (17.6 versus 12.0 per cent; P = 0.148), adverse events (48.5 versus 54.5 per cent; P = 0.221) and mortality (1.1 versus 0.4 per cent; P = 0.432). Hospital stay was significantly shorter in the observation group (2 versus 3 days; P = 0.006). Per-protocol analyses were concordant with the intention-to-treat analyses. Conclusion: Observational treatment without antibiotics did not prolong recovery and can be considered appropriate in patients with uncomplicated diverticulitis. Registration number: NCT01111253 (http://www.clinicaltrials.gov).