The impact of fair colonoscopy preparation on colonoscopy use and adenoma miss rates in patients undergoing outpatient colonoscopy

Background: The impact of fair bowel preparation on endoscopists' recommendations and adenoma miss rates in average-risk patients undergoing colonoscopy is unknown.

Objective: To assess the impact of fair bowel preparation on endoscopists' interval colonoscopy recommendations and miss rates in colonoscopies performed within 3 years of the index colonoscopy in average-risk patients undergoing colorectal cancer screening.

Design: Retrospective chart review.

Setting: Tertiary-care center.

Patients: Average-risk patients undergoing index colonoscopy for colorectal cancer screening between 2004 and 2006.

Intervention: Colonoscopy.

Main outcome measurements: Endoscopists' interval recommendations, adenoma miss rates.

Results: A total of 16,251 colonoscopy records were reviewed over a 2-year period. Of these cases, 1943 colonoscopies were performed for the sole indication of average risk or screening. Of these, fair bowel preparation was reported in 619 patients (31.9%). A repeat colonoscopy within 5 years was recommended in 70.4% of patients. The follow-up colonoscopy compliance rate within 3 years was 55.9%. Adenoma detection rates at index and follow-up colonoscopy were 20.5% and 28.2%, respectively. Of the 39 patients with follow-up colonoscopy within 3 years, the overall adenoma miss rate was 28%. Of the patients with an adenoma identified on follow-up colonoscopy, 13.6% had normal colonoscopy results on index examination.

Limitations: Retrospective design.

Conclusion: Fair bowel preparation led to a deviation from national guidelines with early repeat colonoscopy follow-up recommendations in nearly 60% of average-risk patients with normal colonoscopy results. In patients who returned for repeat colonoscopy within 3 years, the overall adenoma miss rate was 28%. Further guidelines on timing for repeat colonoscopy for fair bowel preparation are needed.