Previous studies examining the effect of fellow participation on adenoma detection rate in colonoscopy have yielded conflicting results, and factors such as adenoma size and location have not been rigorously evaluated.

To examine whether fellow participation during screening, surveillance, or diagnostic colonoscopy affects overall, size-specific, or location-specific adenoma or polyp detection rate.

This was a retrospective study of 2430 colonoscopies performed in our ambulatory surgical center between September 2006 and December 2007, comparing adenoma and polyp detection rates of colonoscopies performed by fellows with supervising staff endoscopists (n = 318) with colonoscopies performed by staff endoscopists without fellow participation (n = 2112). Study participants included patients who underwent screening, surveillance, or diagnostic colonoscopies in our GI suite. Logistic regression analysis was used to evaluate the association of fellow participation with adenoma and polyp detection.

There was evidence of a higher rate of small (<5 mm) adenoma detection in colonoscopies with a fellow present (25% vs 17%, P = .001). This remained significant after multiple-testing adjustment (P ≤ .003 considered significant). Findings were similar, although not significant for small polyps (36% vs 29%, P = .007). There was a trend toward increased adenoma detection in colonoscopies with a fellow present compared with those without (30% vs 26%, P = .11). Multivariable adjustment for potentially confounding variables did not alter these associations.

The study had a retrospective design, and information regarding bowel preparation was not available for 37% of patients.

Fellow involvement was associated with increased detection rates of small adenomas, providing evidence that the presence of a fellow during colonoscopy plays a role in enhancing the effectiveness of the examination.