Antibiotic treatment for uncomplicated and mild complicated diverticulitis: outpatient treatment for everyone.

Purpose: Antibiotic treatment is the treatment of choice for uncomplicated diverticulitis (uD) and can be performed for mild complicated diverticulitis (mcD). In several cases, outpatient treatment (OT) can be undertaken. This study assessed the 1-month failure rate of OT for uD/mcD compared to inpatient treatment (IT), and identified predictive factors for treatment failure.

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: abscess, 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 patients 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 factors of failure necessitating closer follow-up were admission/CT time, Ambrosetti score of 4, and free air around the colon.