Paper of the Month - December

Outpatient treatment without antibiotic for mild acute diverticulitis: Craziness or evidence-based medicine?

December’s paper of the month is a randomized clinical trial focused on the treatment of mild acute diverticulitis: are antibiotic treatment and hospital admission necessary?

Efficacy and Safety of Non-antibiotic Outpatient Treatment in Mild Acute Diverticulitis (DINAMO-study). A Multicentre, Randomised, Open-label, Non-inferiority Trial.

Laura Mora-Lopez, Neus Ruiz-Edo, Oscar Estrada-Ferrer, Maria Luisa Piñana-Campon, Meritxell Labro-Ciurans, Jordi Escuder-Perez, Ricard Sales-Mallafre, Pere Rebasa-Cladera, Salvador Navarro-Soto, Xavier Serra-Aracil, for the DINAMO-study Group

Ann Surg 2021;274:e435–e442

What is known on the subject?

In Western Countries the prevalence of diverticular disease is increasing and a relevant percentage of these patients will suffer an episode of acute diverticulitis (AD) at some point in their lifetime. Although AD is one of the most frequent causes for consultation to the emergency department, the majority of these episodes are not complicated and can be treated conservatively. Assuming an infectious aetiology for AD, treatment has classically been based on antibiotics and hospital admission, even if the scientific basis for this strategy is weak.

In recent years, increasing concerns about antibiotic resistance and the need for a rational use of the healthcare resources have pushed clinicians to question this dogma. Recently, 2 RCTs [1,2] have suggested that antibiotics could be omitted in patients with a first episode of uncomplicated AD, but neither was performed on an outpatient basis. Accordingly to these findings, the Guidelines of the American Society of Colon and Rectal Surgeons have included the non-antibiotic treatment of uncomplicated AD as a valid option. In the same way, outpatient treatment of patients with uncomplicated AD has been shown to be safe and effective [3].

However, the association between non-antibiotic and outpatient treatment for patients with uncomplicated AD has not been studied to date and the majority of Western centres follow the old dogma. Patients with mild AD are still admitted to hospital and treated with antibiotics with consequent increased healthcare costs and risks of antibiotic resistance.

What this study adds

The present study is a prospective, multicentre, open-label, non-inferiority, randomized controlled trial, including patients consulting the emergency department with mild AD diagnosed by CT scanning. Included patients were randomly assigned to control arm with classical treatment (amoxicillin/clavulanic acid + anti-inflammatory and symptomatic treatment) or experimental arm (anti-inflammatory and symptomatic treatment without antibiotic). The study demonstrated that outpatient treatment without antibiotic was not inferior to outpatient treatment with antibiotic in terms of admission rate, emergency department revisits, pain control and complications. None of the 480 patients included in the study needed urgent surgery.

Implications for colorectal practice

The study shows that non-antibiotic outpatient treatment of patients with mild AD is safe and effective and is not inferior to the current standard treatment, without additional complications or serious adverse effects. Therefore, this is a therapeutic approach that could be considered as standard of care, offering the economic advantages of outpatient care and practical advantages of the avoidance of antibiotic treatment without the potential development of antibiotic resistance.



1. Daniels L, Unlu¨ C¸ , de Korte N, et al. Randomized clinical trial of observational versus antibiotic treatment for a first episode of CT-proven uncomplicated acute diverticulitis. Br J Surg. 2017;104:52–61.

2. Chabok A, Pa°hlman L, Hjern F, et al. AVOD Study Group. Randomized clinical trial of antibiotics in acute uncomplicated diverticulitis. Br J Surg. 2012;99:532–539.

3. Biondo S, Golda T, Kreisler E, et al. Outpatient versus hospitalization management for uncomplicated diverticulitis: a prospective, multicenter randomized clinical trial (DIVER Trial). Ann Surg. 2014;259:38–44.



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