Antibiotic treatment for uncomplicated and mild complicated
diverticulitis: outpatient treatment for everyone
Accepted: 20 June 2017 / Published online: 29 June 2017
Springer-Verlag GmbH Germany 2017
Purpose Antibiotic treatment is the treatment of choice for
uncomplicated diverticulitis (uD) and can be performed for
mild complicated diverticulitis (mcD). In several cases, out-
patient treatment (OT) can be undertaken. This study assessed
the 1-month failure rate of OT for uD/mcD compared to inpa-
tient treatment (IT), and identified predictive factors for treat-
Methods All consecutive patients (2006–2012) diagnosed
with uD/mcD by CT scan were retrospectively analyzed.
Acute uD was defined as absence of the following: ab-
scess, fistula, extraluminal contrast, pneumoperitoneum,
and need for immediate percutaneous drainage/surgery.
Acute mcD was defined as complicated diverticulitis with
abscess <4 cm or pneumoperitoneum <2 cm. All patients
received antibiotherapy. Treatment failure was defined as
(re)hospitalization the first month after treatment onset or
need of drainage/surgery during hospitalization. All pa-
tients were contacted using a standardized questionnaire.
Results Out of 540 uD/mcD, IT was offered to 369 patients
(68%) and OT to 171 patients (32%). The IT group had higher
median age, more women, higher median Charlson Index,
more severe median Ambrosetti score, longer median time
in the emergency room, and higher median CRP. Response
rates to the questionnaire were 56% (IT) vs. 62% (OT),
p = 0.18. Failure rates were 32% in IT vs. 10% in OT group,
p < 0.01. Among the uD/mcD patients, admission/CT time
between midnight and 6 AM, Ambrosetti score of 4, and free
air around the colon were risk factors for failure.
Conclusions Outpatient treatment for uncomplicated/mild
complicated diverticulitis is feasible and safe. Prognostic fac-
tors of failure necessitating closer follow-up were admission/
CT time, Ambrosetti score of 4, and free air around the colon.
Approximately 20% of patients with diverticular disease
will present at least one episode of acute diverticulitis
[1–4]. Recently, the treatment of diverticulitis has evolved
to become more conservative even without antibiotics 
and less invasive with percutaneous drainage or laparo-
scopiclavage. Indications for emergency surgery are
now restricted to gross purulent or fecal peritoneal con-
tamination, septic shock, or failure of conservative treat-
ment . In addition, the majority of patients present with
uncomplicated diverticulitis (uD), i.e., without complica-
tions such as abscess, bleeding, fistula, stenosis, or perfo-
ration with free air . Patients with small abscess or low
free air (mild complicated diverticulitis, mcD) can also be
treated with antibiotics according to recent studies .
Several studies showed that outpatient treatment (OT) of
uD and mcD was feasible and safe [9–11]. It has also
been shown that OT was cost-beneficial and cost-
effective inducing important savings for the hospital and
the general health care system [10, 12, 13].
This paper has been presented in parts at the 102nd Annual Congress of
the Swiss Surgical Society, May 20–22, 2015, Bern, Switzerland.
* Nicolas Demartines
Department of Visceral Surgery, Lausanne University Hospital
(CHUV), Rue du Bugnon 46, 1011 Lausanne, Switzerland
Emergency Department, Lausanne University Hospital (CHUV),
Int J Colorectal Dis (2017) 32:1313–1319