Therapeutic strategies for the prevention of acute diverticulitis according to the Diverticular Inflammation and Complication Assessment endoscopic score: a post hoc analysis of a prospective international study

Objective The onset of acute diverticulitis (AD) is a significant concern, yet the optimal preventive strategy is unclear. Methods This multicentre, prospective cohort study included 1945 patients with newly diagnosed colonic diverticula and scored according to Diverticular Inflammation and Complication Assessment (DICA) classification. At baseline, patients were assigned to one of five treatment strategies: no treatment, a high-fibre diet, mesalamine, rifaximin, or a combination of mesalamine and rifaximin. The primary outcome was the development of AD within 3 years. Energy balancing weighting and multivariable weighted Cox regression were used to estimate the causal treatment effects from nonrandomised data. Results During the follow-up period, 140 cases of AD were reported. The crude 3-year risk was: 3.3% (no treatment), 5.9% (high-fibre diet), 9.5% (mesalamine), 11.8% (rifaximin), and 17.1% (mesalamine plus rifaximin). Mesalamine was associated with a lower hazard risk of AD compared to rifaximin [hazard ratio (HR) = 0.42; 95% confidence interval (CI): 0.19–0.94] and combination therapy (HR = 0.37; 95% CI: 0.15–0.88). Rifaximin was associated with a higher hazard risk compared to no treatment. Mesalamine was most beneficial for patients classified as DICA 2, with a 77% (HR = 0.23; 95% CI: 0.08–0.62) and 84% (HR = 0.16; 95% CI: 0.05–0.53) lower hazard of AD compared to rifaximin and combination therapy, respectively. Conclusion Mesalamine may be a better alternative in patients classified as DICA 2; however, its benefit over no treatment remains uncertain.