Recurrence of diverticulitis is frequent within 5 years from the uncomplicated first attack, and its prophylaxis is still unclear. We have undertaken a multicentre, randomised, double-blind, placebo-controlled pilot study in order to evaluate the role of mesalazine in preventing diverticulitis recurrence as well as its effects on symptoms associated to diverticular disease.

Background and aim: Recurrence of diverticulitis occurs in 19-54% of patients within 5 years after uncomplicated first attack. A few open clinical trials suggested the usefulness of 5-ASA compounds in these patients. We have undertaken a multicentre randomized pilot placebo-controlled study to evaluate the prophylactic role of mesalazine in preventing recurrence of diverticulitis as well as its effects on symptoms associated to diverticular disease. Material and methods: 105 patients with uncomplicated diverticulitis in the previous 6 months were randomized to receive in a double-blind fashion for 24 months: (a) mesalazine 800 mg bid for 10 days every month or (b) matching placebo. The primary efficacy endpoints were the diverticulitis recurrence at ITT analysis and the time of relapse (TTR). Clinical evaluations were performed using the Therapy Impact Questionnaire (TIQ) for physical condition and quality of life at admission and at 3-month-intervals. Treatment tolerability and use of additional GI-drugs were also evaluated at baseline visit and every 6 and 3 months, respectively. Results: 96 patients (mean-age 61.5 years), 47 on mesalazine and 49 on placebo, were analyzed. Relative risk (RR) of diverticulitis relapse in mesalazine vs placebo group was 1.04, 0.87, 0.69 and 0.48 at 6, 12, 18 and 24 months, respectively (p: ns). The average time-to-relapse was 219 days for mesalazine-treated-group and 370 days for the placebo-group (p: ns). Mean values of TIQ for physical condition at 24 months was significantly better in mesalazine than in placebo group (p =0.021); average additional drug consumption was also significantly lower (-20.4%, p=0.028) during mesalazine than placebo treatment. No significant difference in the development of side effects or changes of the laboratory parameters were recorded in the two groups. Conclusions: Intermittent prophylactic treatment with mesalazine reduces the relative risk of diverticulitis recurrence after 24 months (0.48, 95%CI 0.201.15). Patient physical conditions are significantly improved by mesalazine, with a significant reduction of the additional consumption of other GI drugs.