Colonic Investigation following acute diverticulitis in Northland, New Zealand

AIM: Diverticulitis is common and increasing in incidence. The risk of malignancy in those with uncomplicated diverticulitis is estimated to be 0.7%, compared with 10% in complicated diverticulitis. Newer guidelines suggest colonic investigation in patients with complicated diverticulitis only. We aim to investigate which patients in Northland undergo colonic investigation following an episode of diverticulitis, define malignancy detection rate and aid in the formulation of local guidelines.METHODS: A retrospective review of adults admitted to Whangarei Hospital with diverticulitis between 2015 and 2019. Patients were classified as complicated or uncomplicated based on the Hinchey classification radiologically or intra-operatively. Patients were followed up to a minimum of 24 months.RESULTS: Three hundred and forty-nine patients were included. One hundred and eighty-two (48%) patients underwent colonic investigation following admission with diverticulitis; 50 with complicated and 132 with uncomplicated disease. The rate of colonic investigation between the groups was similar, at 53% and 47% respectively. Two patients (1.1%) were found to have a colonic malignancy, both in the uncomplicated group. The performance of a colonic investigation was not associated with complicated disease, ethnicity, gender or age on univariate or multivariate analysis.CONCLUSION: Colonic investigation following an admission for acute diverticulitis in Northland is not aligned with recently published guidelines. The rate of colonic malignancy found was low. Larger local studies are needed to guide clinicians and maximise efficiency of resource utilisation.