BACKGROUND Although colonoscopy verification is warranted after an acute event of diverticulitis to exclude underlying malignancy, little evidence is available to support the recommendations.

AIM The aim of this study was to examine whether subsequent colonoscopy is warranted in patients with diverticulitis on computed tomography (CT).

METHODS The study was composed of patients diagnosed with acute diverticulitis on CT scan from January 2001 to March 2013. Patients who had subsequent colonoscopy within a year from the date of CT were included. For each diverticulitis case, two age- (± 5 years) and sex-matched controls were identified from healthy individuals who had received screening colonoscopy. We evaluated the diagnostic yield of advanced colonic neoplasia in colonoscopy.

RESULTS One hundred and forty-nine patients underwent subsequent colonoscopy within a year from the date of CT. Among the patients, 11 (7.4 %) had colon cancer and 5 (3.4 %) had advanced adenoma. A case-control study revealed that the odds of detecting an advanced neoplasia among patients with diverticulitis on CT were approximately 8.8 times greater than in the age- and sex-matched controls [OR 8.84; 95 % CI 2.90-26.96; p < 0.001]. On analysis of the diverticulitis group, age (≥ 50 years) is an independent risk factor for detecting advanced colonic neoplasia.

CONCLUSIONS The yield of advanced colonic neoplasia was substantially higher in patients with acute diverticulitis than in asymptomatic, average-risk individuals. Colonoscopy verification is warranted in patients with diverticulitis detected on CT, especially in those aged 50 years or older.