Multicentre study of non-surgical management of diverticulitis with abscess formation

Background: Treatment strategies for diverticulitis with abscess formation have shifted from (emergency) surgical treatment to non-surgical management (antibiotics with or without percutaneous drainage (PCD)). The aim was to assess outcomes of non-surgical treatment and to identify risk factors for adverse outcomes. Methods: Patients with a first episode of CT-diagnosed diverticular abscess (modified Hinchey Ib or II) between January 2008 and January 2015 were included retrospectively, if initially treated non-surgically. Baseline characteristics, short-term (within 30 days) and long-term treatment outcomes were recorded. Treatment failure was a composite outcome of complications (perforation, colonic obstruction and fistula formation), readmissions, persistent diverticulitis, emergency surgery, death, or need for PCD in the no-PCD group. Regression analyses were used to analyse risk factors for treatment failure, recurrences and surgery. Results: Overall, 447 patients from ten hospitals were included (Hinchey Ib 215; Hinchey II 232), with a median follow-up of 72 (i.q.r. 55-93) months. Most patients were treated without PCD (332 of 447, 74.3 per cent). Univariable analyses, stratified by Hinchey grade, showed no differences between no PCD and PCD in short-term treatment failure (Hinchey I: 22.3 versus 33 per cent, P=0.359; Hinchey II: 25.9 versus 36 per cent, P=0.149) or emergency surgery (Hinchey I: 5.1 versus 6 per cent, P=0.693; Hinchey II: 10.4 versus 15 per cent, P=0.117), but significantly more complications were found in patients with Hinchey II disease undergoing PCD(12 versus 3.7 per cent; P=0.032). Multivariable analyses showed that treatment strategy (PCD versus no PCD) was not independently associated with short-term treatment failure (odds ratio (OR) 1.47, 95 per cent c.i. 0.81 to 2.68), emergency surgery (OR 1.29, 0.56 to 2.99) or long-term surgery (hazard ratio 1.08, 95 per cent c.i. 0.69 to 1.69). Abscesses of at least 3 cm in diameter were associated with short-term treatment failure (OR 2.05, 1.09 to 3.86), and abscesses of 5 cm or larger with the need for surgery during short-term follow-up (OR 2.96, 1.03 to 8.13). Conclusion: The choice between PCD with antibiotics or antibiotics alone as initial non-surgical treatment of Hinchey Ib and II diverticulitis does not seem to influence outcomes.