Nonantibiotic Outpatient Therapy Safe and Effective for Mild Acute Diverticulitis

Investigators assessed differences in rates of admission among patients with mild acute diverticulitis treated with or without antibiotics in an outpatient setting.

Nonantibiotic outpatient treatment in patients with mild acute diverticulitis is safe and effective and is not inferior to current standard treatment, according to a study in the Annals of Surgery.

The randomized controlled DINAMO trial was conducted in 15 colorectal surgery units at acute care secondary and tertiary hospitals in Catalonia, Spain. Patients aged 18 to 80 years with modified Neff (mNeff) grade 0 acute diverticulitis on abdominal computed tomography scans, no acute diverticulitis episodes in the previous 3 months, and no antibiotic treatment for any reason in the last 2 weeks, among other criteria, were included in the analysis.

Participants in the experimental arm (non-ATB group) received anti-inflammatory and symptomatic treatment with 600 mg/8 h ibuprofen alternating with 1 g/8 h acetaminophen. Those in the control arm (ATB group) received 875/125 mg/8 h amoxicillin/clavulanic acid in addition to the same anti-inflammatory and symptomatic treatment.

Medical treatment with or without antibiotics was administered for 7 days. Both groups underwent the same clinical controls at 2, 7, 30, and 90 days after the episode. Hospital admission was the primary endpoint.

A total of 849 patients diagnosed with mild acute diverticulitis presented to the emergency department from November 2016 to January 2020. Of this group, 480 patients were randomly assigned to the non-ATB group (n=242) or the ATB group (n=238).

Revisits to the emergency department led to 22/480 (4.6%) admissions — 14/238 (5.8%) in ATB group and 8/242 (3.3%) in the non-ATB group, with a 2.58% difference (95% CI, 6.32 to -1.17; P =.19). The non-ATB group demonstrated noninferiority vs the ATB group (Δ < 7%).

Among the study cohort, 447 patients did not return to the emergency department, and 40/480 (8.3%) revisits corresponded with 33 patients — 16/238 (6.72%) in the ATB group and 17/242 (7.02%) in the non-ATB group (mean difference, -0.3; 95% CI, 4.22 to -4.83).

The ATB group (13/230; 5.7%) had a higher degree of pain at the 2-day clinical control vs the non-ATB group (5/221; 2.3%) (mean difference, 3.39; 95% CI, 6.96 to -0.18). Participants in the non-ATB group had higher pain scores at later controls, although the differences were not statistically significant.

The main study limitation is the significant number of patients who were excluded due to the strict selection criteria. Additionally, because the physicians were involved in decisions regarding hospital admission, observer/selection bias is possible. Furthermore, the study did not include use of a placebo.

“There were no additional complications or serious adverse effects compared with the current standard treatment,” stated the researchers. “Therefore, this is a safe and effective therapeutic approach that can be considered as routine practice, offering the economic advantages of outpatient care and the practical advantages of the avoidance of antibiotic treatment,” they concluded.


Mora-López L, Ruiz-Edo N, Estrada-Ferrer O, et al. Efficacy and safety of nonantibiotic outpatient treatment in mild acute diverticulitis (DINAMO-study): a multicentre, randomised, open-label, noninferiority trial. Ann Surg. 2021;274(5):e435-e442. doi: 10.1097/SLA.0000000000005031