Original article
Clinical endoscopy
Prevalence of missed adenomas in patients with inadequate bowel preparation on screening colonoscopy

Presented at Digestive Disease Week, June 9, 2011, Chicago, Illinois.
https://doi.org/10.1016/j.gie.2012.01.005Get rights and content

Background

The prevalence of missed polyps in patients with inadequate bowel preparation on screening colonoscopy is unknown.

Objective

To determine the prevalence of missed adenomas in average-risk patients presenting for screening colonoscopy who are found to have inadequate bowel preparation.

Design

Retrospective chart review. Endoscopy and pathology reports were examined to determine the characteristics of polyps. Data from repeat colonoscopies were collected through 2010.

Setting

Outpatient endoscopy center at an academic medical center.

Patients

This study involved patients who underwent outpatient average-risk screening colonoscopy between 2004 and 2009 documented to have inadequate bowel preparation and who had colonoscopy to the cecum.

Main Outcome Measurements

Initial adenoma detection rate and adenoma detection rate on follow-up examination.

Results

Inadequate bowel preparation was reported on 373 patients, with an initial adenoma detection rate of 25.7%. Of 133 patients who underwent repeat colonoscopy, 33.8% had at least 1 adenoma detected, and 18.0% had high-risk states detected (≥3 adenomas, 1 adenoma ≥1 cm, or any adenoma with villous features or high-grade dysplasia). Per-adenoma miss rate was 47.9%. Among patients with at least 1 adenoma on repeat colonoscopy, 31.1% had no polyps on initial colonoscopy; mean time between colonoscopies was 340 days. Among patients with high-risk states, 25.0% had no polyps seen on initial colonoscopy; mean time between colonoscopies was 271 days.

Limitations

Retrospective design.

Conclusion

Adenomas and high-risk lesions were frequently detected on repeat colonoscopy in patients with inadequate bowel preparation on initial screening colonoscopy, suggesting that these lesions were likely missed on initial colonoscopy.

Section snippets

Methods

This study was conducted at the outpatient endoscopy center at Washington University in St. Louis School of Medicine and Barnes-Jewish Hospital and was reviewed and approved by the institutional review board. A waiver of informed consent was obtained given the study's retrospective nature. Data were collected via the electronic institutional database.

By using our outpatient endoscopy database, screening colonoscopies performed between August 1, 2004 and July 31, 2009 were collected. Initial

Results

Figure 1 summarizes our study design and patient inclusion for analysis. Initial search criteria of our institutional endoscopy database identified 518 colonoscopies performed for average-risk screening and completed to the cecum in which the bowel preparation quality was defined as poor, inadequate, or unsatisfactory. After manual review of these colonoscopy reports, 145 were excluded, giving a total of 373 colonoscopies that were included in our analysis. Reasons for exclusion included the

Discussion

Current guidelines do not address the appropriate management of patients found to have inadequate bowel preparation during average-risk screening colonoscopy. Patients with extremely poor bowel preparation usually will have their procedures aborted with instructions to repeat the examination. However, there are a substantial number of patients in whom the bowel preparation is sufficient to allow completion of the examination, but obscuring stool results in visualization that is inadequate to

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DISCLOSURE: All authors disclosed no financial relationships relevant to this publication.

If you would like to chat with an author of this article, you may contact Dr Wang at [email protected].

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