Colovesical fistula, a serious complication of colonic diverticulitis, often requires surgical intervention. As the epidemiological data for colovesical fistula associated with colonic diverticulitis in Japan are limited, this study investigated its incidence and characteristics using a claims database. This retrospective study analyzed the JMDC Claims Database (January, 2005 to August, 2023). Patients with colonic diverticulitis were identified based on diagnosis codes and concurrent antibiotic treatment. Patients diagnosed with colovesical fistulas who underwent surgery were included in the analysis. Patients with fistulas associated with cancer or inflammatory bowel disease such as ulcerative colitis and Crohn’s disease were excluded. In total, 42,825 patients with colonic diverticulitis were identified and colovesical fistula developed in 185 (0.43%) of these patients (0.63% in men and 0.07% in women). The median duration from diverticulitis to fistula diagnosis was 0 days, with 73.2% of patients diagnosed simultaneously with, or prior to, diverticulitis. Surgery was performed a median of 49 days after diagnosis. This first Japanese epidemiological study on colovesical fistulas highlights its low incidence, sex differences, and frequent diagnosis before or with colonic diverticulitis. These findings emphasize the importance of recognizing the diverse clinical presentations for a timely diagnosis and better management.
Omotaka et al. (Tue,) studied this question.