Inadequate Boston Bowel Preparation Scale scores predict the risk of missed neoplasia on the next colonoscopy

Background and aims: The risks of missed findings after inadequate bowel preparation are not fully characterized in a diverse cohort. We aimed to evaluate the likelihood of missed polyps after an inadequate preparation as assessed by using the Boston Bowel Preparation Scale (BBPS).

Methods: In this observational study of prospectively collected data within a large, national, endoscopic consortium, we identified patients aged 50 to 75 years who underwent average-risk screening colonoscopy (C1) followed by a second colonoscopy for any indication within 3 years (C2). We determined the polyp detection rates (PDRs) and advanced PDRs during C2 stratified by C1 BBPS scores.

Results: Among segment pairs without polyps at C1 (N = 601), those with inadequate C1 BBPS segment scores had a higher PDR at C2 (10%) compared with those with adequate bowel preparation at C1 (5%; P = .04). Among segment pairs with polyps at C1 (N = 154), segments with inadequate bowel preparation scores at C1 had higher advanced PDRs at C2 (20%) compared with those with adequate bowel preparation scores at C1 (4%; P = .03). In multivariable analysis, the presence of advanced polyps at C1 (adjusted odds ratio [OR] 3.5; 95% confidence intervals [CIs], 1.1-10.8) but not inadequate BBPS scores at C1 (adjusted OR 1.8; 95% CI, 0.6-5.1) was associated with a significantly increased risk of advanced polyps at C2.

Conclusions: Inadequate BBPS segment scores generally are associated with higher rates of polyps and advanced polyps at subsequent colonoscopy within a short timeframe. The presence of advanced polyps as well as inadequate BBPS segment scores can inform the risk of missed polyps and help triage which patients warrant a timely repeat colonoscopy.