Letter: Bowel Preparation Quality in Patients With Crohn's Disease

Adequate bowel preparation is crucial for optimal visualisation and lesion detection and remains a key determinant of colonoscopy quality [1, 2]. Up to one-quarter of colonoscopies are conducted with inadequate bowel preparation, leading to reduced diagnostic yield and detection of nonpolypoid flat lesions, prolonged procedure time and an increased burden of repeat colonoscopies [2, 3].

Several validated scales exist for the assessment of bowel preparation quality, however, an area of unmet need is validated scores for patients with inflammatory bowel disease (IBD), where endoscopy is essential to diagnosis, disease assessment, management and cancer surveillance. The presence of strictures, severe inflammation and insufficient bowel preparation may present a unique challenge to colonoscopy quality in IBD. Additionally, various adverse predictors of poor bowel preparation have been identified in IBD patients [4-6]. There is a clear need for robust and reproducible colonoscopy quality control measures in this sub-population [7].

Solitano et al. evaluated the performance of four existing bowel preparation quality instruments—Boston Bowel Preparation Scale (BBPS), a modified BBPS (mBBPS), Harefield Cleansing Scale, and Bowel Cleansing Assessment Scale—in 50 endoscopy videos with Crohn's disease (CD) [8]. Their findings demonstrated ‘moderate’ to ‘substantial’ inter-rater and intra-rater reliability, and high correlation coefficients between instruments and the visual analogue scale. An important finding is that all instruments performed well in terms of overall reliability and the authors concluded that instrument selection for use in clinical practice should be based on familiarity and local practice.

This is an important study to support the use of these instruments as reliable and valid measures of bowel preparation quality in CD—particularly in those with active luminal disease, with 72.5% of the procedures having an SES-CD score > 3. Areas for further exploration include the instruments' ease of use, and the degree of ambiguity in interpreting the scores for each instrument. These factors were not discussed in this paper, however, would be highly relevant in clinical practice and informing consensus guidelines. Furthermore, the observed numerical differences in correlation scores would be of interest to explore in further large studies.

Important study limitations include the small sample size, which makes it challenging to comment on the applicability of these findings to specific CD subgroups. We look forward to further studies evaluating the reliability of quality scales particularly in penetrating, stricturing, and perianal fistulising CD cohorts with active proctitis. The cohort heterogeneity presents another limitation in applying these data to the general CD population. For instance, assessing colon preparation scores in a cohort that includes many patients with isolated ileal disease (14.3% of procedures) introduces interpretative complexity. There may also be differences in target bowel preparation quality depending on the procedure indication, such as cancer surveillance compared to disease assessment.

In conclusion, this study provides support for the use of existing bowel preparation quality instruments in CD. Further studies are required to address the limitations related to sample size and subgroup applicability.