S465 The Effectiveness of Post-Acute Diverticulitis Colonoscopy in Detecting Advanced Neoplasia: Insights From a Large Retrospective Cohort

Introduction: Acute diverticulitis (AD) leads to approximately 208,000 hospitalizations annually in the U.S. Current guidelines recommend colonoscopy following any complicated AD episode or a first episode of uncomplicated AD, typically within 6–8 weeks, unless a recent high-quality colonoscopy was performed. Despite this, practice patterns vary, and many gastroenterologists perform post-AD colonoscopy regardless of individual risk. The true diagnostic yield of this practice remains uncertain. This study assessed the effectiveness of post-AD colonoscopy in detecting adenomatous polyps, advanced adenomas, and colorectal cancer (CRC). Methods: We conducted a retrospective study of post-AD colonoscopies performed at 2 tertiary care academic centers from May 2015-September 2024. Inclusion required CT-confirmed AD. We collected demographic, radiologic, and colonoscopic data including AD severity (uncomplicated vs complicated), types of complications, polyp characteristics, and detection of advanced adenomas (≥1 cm, tubule-villous histology, high-grade dysplasia) or CRC. Data were further stratified by patients up to date (UTD) and not up to date (not UTD) with CRC screening. Results: Of 390 patients, 48.7% had complicated AD. Median age at colonoscopy was 59 years (interquartile range 45–65); 42.3% were men. Advanced adenomas were detected in 3.3%, and CRC in 1.0%. Most advanced adenomas were found in the ascending and sigmoid colon. Complicated AD patients were significantly younger (P = 0.015), while smoking history and advanced adenoma presence lost significance after stratification. Comparing patients UTD vs not UTD with CRC screening, age remained significantly different (P < 0.001), with not UTD patients being older. Body mass index lost significance (P = 0.348 vs 0.048). Adenocarcinoma was only identified in patients not UTD with CRC screening (P = 0.022). Conclusion: This study shows that complicated AD is associated with younger age, and while smoking history and advanced adenoma presence were initially significant, these lost significance after stratification. Importantly, adenocarcinoma was detected exclusively in patients not UTD with CRC screening, likely confounded by older age. These findings support prioritizing post-AD colonoscopy for patients not UTD with CRC screening and suggest that non-invasive screening strategies (e.g., Cologuard) could be considered for those already UTD, potentially reducing unnecessary procedures and associated costs. Further prospective studies are warranted to validate these observations.