Impact of bowel preparation on surveillance colonoscopy interval

Background/Aims. Atpresent there are no guidelines for colonoscopy surveillance interval in subjects with unsatisfactory bowel preparation. Study was designed to compare outcomes of repeat colonoscopy at different surveillance intervals in patients with unsatisfactory preparation on index exam. Methods. Ten thousand nine hundred and eight colonoscopies were done during the study period. Patients with index colonoscopy exam complete up to cecum but suboptimal bowel prep were included. Results.Two hundred and ninety-seven patients met the inclusion criteria. The interval for repeat colonoscopy was <1 year in 38.5%, 1-2 years in 33.3%, 2-3 years in 16.7%, and 3-5 years in 11.5% subjects. Adenoma detection rate (ADR) was 24%, high-risk adenoma detection rate (HR-ADR) was 8.4%, and colorectal cancer detection rate was 1.7%. The HR-ADR based on surveillance intervals <1 year, 1-2 years, 2-3 years, and 3-5 years was 8%, 7.9%, 2%, and 19.4%, respectively. The HR-ADR was significantly higher at surveillance interval 3-5 years (p < 0.05). Conclusion. Colonoscopies repeated at interval >3 years showed a significant HR-ADR. The study indicates that a surveillance interval of 3 years can be reasonable for subjects having an index colonoscopy with suboptimal/fair/poor bowel prep and complete colon examination. Colonoscopy should be repeated earlier if symptoms develop.