ARTICLELong-Term Effects of Omitting Antibiotics in Uncomplicated Acute Diverticulitisvan Dijk, S. T. MD1; Daniels, L. MD, PhD1,2; Ünlü, Ç. MD, PhD3; de Korte, N. MD, PhD4; van Dieren, S. PhD5; Stockmann, H. B. MD, PhD4; Vrouenraets, B. C. MD, PhD6; Consten, E. C. MD, PhD7; van der Hoeven, J. A. MD, PhD8; Eijsbouts, Q. A. MD, PhD4; Faneyte, I. F. MD, PhD9; Bemelman, W. A. MD1; Dijkgraaf, M. G.5; Boermeester, M. A. MD1 for the Dutch Diverticular Disease (3D) Collaborative Study GroupAuthor Information 1Department of Surgery, Academic Medical Center, Amsterdam, Netherlands. 2Department of Surgery, Westfries Gasthuis, Hoorn, Netherlands. 3Medical Centre Alkmaar, Alkmaar, Netherlands. 4Spaarne Gasthuis, Haarlem and Hoofddorp, Netherlands. 5Clinical Research Unit, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands. 6OLVG, Amsterdam, Netherlands. 7Meander Medical Centre, Hoogland, Amersfoort, Netherlands. 8Albert Schweitzer Hospital, Dordrecht, Netherlands. 9Ziekenhuisgroep Twente Hospital, Almelo, Netherlands. Correspondence: S.T.D. (email: email@example.com) or M.A.B. (email: firstname.lastname@example.org) SUPPLEMENTARY MATERIAL accompanies this paper at http://links.lww.com/AJG/A230, http://links.lww.com/AJG/A232 Received 10 August 2017; accepted 3 February 2018; Published online 11 May 2018 see related editorial on page 949 American Journal of Gastroenterology: July 2018 - Volume 113 - Issue 7 - p 1045–1052 doi: 10.1038/s41395-018-0030-y Buy SDC Metrics Abstract BACKGROUND: Traditionally uncomplicated acute diverticulitis was routinely treated with antibiotics, although evidence for this strategy was lacking. Recently, two randomized clinical trials (AVOD trial and DIABOLO trial) published short-term results of omitting antibiotics compared to routine antibiotic treatment. Both showed no significant differences regarding recovery from the initial episode, as well as rates of complicated or recurrent diverticulitis and sigmoid resection. However, both studies showed a trend of higher rates of sigmoid resection in the observational groups. Here, the long-term effects of omitting antibiotics in first episode uncomplicated acute diverticulitis were assessed. METHODS: A total of 528 patients with CT-proven, primary, left-sided, uncomplicated acute diverticulitis were randomized to either an observational or an antibiotic treatment strategy (DIABOLO trial). Outcome measures were complicated diverticulitis, recurrent diverticulitis and sigmoid resection at 24 months' follow up. Differences between the groups were explored and risk factors were identified using multivariable logistic regression. RESULTS: Complete case analyses showed no difference in rates of recurrent diverticulitis (15.4% in the observational group versus 14.9% in the antibiotic group;p= 0.885), complicated diverticulitis (4.8% versus 3.3%;p= 0.403) and sigmoid resection (9.0% versus. 5.0%;p= 0.085). Young patients (<50 years) and patients with a pain score at presentation of 8 or higher on a visual analogue pain scale were at risk for complicated or recurrent diverticulitis. In this multivariable analysis, treatment type (with or without antibiotics) was not an independent predictor for complicated or recurrent diverticulitis. CONCLUSION: Omitting antibiotics in the treatment of uncomplicated acute diverticulitis did not result in more complicated diverticulitis, recurrent diverticulitis or sigmoid resections at long-term follow up. As the DIABOLO trial was not powered for these secondary outcome measures, some uncertainty remains whether (small) non-significant differences could be true associations. © The American College of Gastroenterology 2018. All Rights Reserved.