Validation of the Harefield Cleansing Scale: a tool for the evaluation of bowel cleansing quality in both research and clinical practice

Abstract

Background: Variations in bowel cleansing quality before colonoscopy can cause confounding of results within clinical trials and inappropriate treatment decisions in clinical practice. A new tool-the Harefield Cleaning Scale-has been developed, which addresses the limitations of existing scales.

Objective: Validation exercise for the new cleansing scale.

Design: Retrospective validation study.

Setting: Various colonoscopy units in France.

Patients: Patients who had a total of 337 colonoscopies recorded.

Intervention: Video-recorded colonoscopy.

Main outcome measurements: Comparisons of 2 scoring systems to assess direct correlation, interrater reliability, internal consistency, and test-retest reliability, based on assessment of video recordings from 337 colonoscopies.

Results: Correlation analysis for expert scores by using the 2 scales yielded a Spearman correlation coefficient of 0.833. Similarly, the comparison of the segmental sum score revealed a Spearman correlation coefficient of -0.778. Cross-tabulation for successful colon cleansing was 92.88% versus unsuccessful colon cleansing in 7.12%. Reliability assessment indicated an acceptable internal consistency with a Cronbach alpha coefficient of 0.81. Test-retest reliability demonstrated an overall agreement of 0.639 (kappa statistic). Receiver operating characteristic analysis versus Aronchick Scale scores yielded an area under the curve of 0.945, with sensitivity of 99% and specificity of 83% at the optimum score cut-off point.

Limitations: Test-retest reliability was assessed by using a different patient population to the other measures. There were insufficient patient numbers to assess performance by using adenoma detection rate.

Conclusion: This validation analysis has demonstrated that the Harefield Cleansing Scale is a robust, reliable, and consistent tool that has the potential to improve the effective standardization of bowel preparation assessment in both clinical and research practice.