Few bowel-preparation rating scales have been validated. Most scales were intended
for comparing oral purgatives and fail to account for washing and/or suctioning by
the endoscopist. This limits their utility in studies of colonoscopy outcomes, such
as polyp-detection rates.
To develop a valid and reliable scale for use in colonoscopy outcomes research.
Academic medical center.
We developed the Boston bowel preparation scale (BBPS), a 10-point scale that assesses
bowel preparation after all cleansing maneuvers are completed by the endoscopist.
We assessed interobserver and intraobserver reliability by using video footage of
colonoscopies viewed on 2 separate occasions by 22 clinicians. We then applied the
BBPS prospectively during screening colonoscopies and compared BBPS scores with clinically
meaningful outcomes, including polyp-detection rates and procedure times.
The intraclass correlation coefficient (a measure of interobserver reliability) for
BBPS scores was 0.74. The weighted kappa (a measure of intraobserver reliability)
for scores was 0.77 (95% CI, 0.66-0.87). During 633 screening colonoscopies, the mean
(SD) BBPS score was 6.0 +/- 1.6. Higher BBPS scores (> or =5 vs <5) were associated
with a higher polyp-detection rate (40% vs 24%, P < .02). BBPS scores were inversely
correlated with colonoscope insertion (r = -0.16, P < .003) and withdrawal (r = -0.23,
P < .001) times.
The BBPS is a valid and reliable measure of bowel preparation. It may be well suited
to colonoscopy outcomes research because it reflects the colon's cleanliness during
the inspection phase of the procedure.