Performance of bowel preparation quality scales in patients with Crohn's disease

Summary Background The performance of bowel preparation (BP) in patients with Crohn's disease (CD) is unknown. Aims To evaluate the operating properties of instruments used to assess BP quality in patients with CD. Methods We used the Boston Bowel Preparation Scale, modified Boston Bowel Preparation Scale, Harefield Cleansing Scale, Food and Drug Administration Bowel Cleansing Assessment Scale (BCAS), and a 100‐mm visual analogue scale of bowel cleanliness to assess BP quality in 50 videos from 40 patients with CD. We assessed endoscopic activity with the Simple Endoscopic Score for CD (SES‐CD). Assessments were on endoscope insertion and withdrawal. Reliability was quantified using the intraclass correlation coefficient (ICC). We assessed validity by within‐patient correlation between instruments and the visual analogue scale using mixed‐effect models. The correlation between BP quality and SES‐SD scores was assessed using Spearman's rho. Results Inter‐ and intra‐rater reliability for all BP quality instruments was substantial (ICC ≥0.61) except for the Food and Drug Administration BCAS on insertion (inter‐rater reliability ICC ≥0.41). The visual analogue scale had substantial inter‐ and almost perfect (ICC ≥0.81) intra‐rater reliability. Correlation coefficients for the validity of the instruments exceeded 0.58. BP quality and endoscopic disease activity scores in the colon were negatively correlated. Conclusion Most existing instruments reliably assess BP quality in patients with CD. These results support the use of these instruments in clinical practice, provide a framework for scoring BP quality in CD clinical trials, and support evaluation of novel BP agents in patients with CD.