Adenoma Detection on Repeat Colonoscopy after Previous Inadequate Preparation

Abstract

AIM: Inadequate bowel preparation is associated with reduced adenoma detection. We sought to determine whether the adenoma miss rate during colonoscopy with inadequate preparation is significantly greater than the adenoma miss rate reported with tandem colonoscopy. METHODS: We reviewed records of all patients at our tertiary care center with an inadequately cleansed index colonoscopy between 2/1/2009-2/28/2010, who underwent repeat colonoscopy within 18 months. The primary endpoint was the overall adenoma miss rate. A two-sided test with alpha 0.05 had 80% power to distinguish an adenoma miss rate of about 33% compared to 22% reported with tandem colonoscopy. 910 patients had inadequate cleansing, and 127 met inclusion criteria including repeat colonoscopy within 18 months. RESULTS: The overall adenoma miss rate was significantly greater than reported with tandem colonoscopy (52% vs. 22%, p=0.001). Miss rates were higher for all adenoma size categories (57% vs. 26% for <5 mm, p=0.001; 37% vs. 13% for 5-9 mm, p=0.002; 47% vs. 2% for ≥10 mm, p=0.001). Accounting for adenomas found on repeat, the recommended surveillance interval shortened for 27% of patients. Factors predicting failure to undergo repeat exam included cecal intubation (OR=3.99, 95% CI: 1.99 to 8.02) and endoscopist recommendation for repeat exam >1 year (OR=11.0, 95% CI: 5.81 to 20.9). CONCLUSION: The adenoma miss rate during colonoscopy with inadequate preparation is significantly higher than reported with tandem colonoscopy. Our findings support performing early repeat colonoscopy after inadequate preparation. © 2013 ACT. All rights reserved.