Specialty differences in polyp detection, removal, and biopsy during colonoscopy

Background: Colonoscopy is a technically complex procedure commonly performed to detect and remove colorectal pathology. This study examined the influence of provider characteristics on polyp detection, polyp removal, and diagnostic biopsy rates.

Methods: We conducted a retrospective cross-sectional study using a 20% sample of 2003 Medicare claims. Primary outcome measures were use of diagnostic biopsy, polyp detection, and polyp removal. We used generalized estimating equations to identify independent predictors of the outcomes, adjusting for patient and provider characteristics.

Results: Among 328,167 outpatient colonoscopies, polyp detection and removal rates were significantly lower for nongastroenterologists than gastroenterologists, with adjusted relative risk for polyp detection between 0.80 (95% confidence interval [CI], 0.77-0.83) for general surgeons and 0.93 (95% CI, 0.89-0.98) for internists. Compared with gastroenterologists, diagnostic biopsy was significantly less likely for general (relative risk [RR] 0.69; 95% CI, 0.65-0.74) or colorectal surgeons (RR 0.58; 95% CI, 0.52-0.65). The likelihood of polyp detection and removal was higher for physicians in the middle 2 quartiles of annual colonoscopy volume, but similar for physicians in the highest and lowest volume quartiles. Polyp detection and removal were significantly less likely for examinations in ambulatory surgery centers or offices than hospital outpatient settings, while diagnostic biopsy was significantly less likely in office settings.

Conclusions: Physician specialty, annual colonoscopy volume, and site of service are significant predictors of polyp detection, polyp removal, and diagnostic biopsy. These findings may have important implications for the effectiveness of colonoscopy.