Colonoscopy performance monitoring: do we need to adjust for case mix?

Abstract

Introduction

Overall caecum intubation rate(oCIR) and overall polyp detection rate(oPDR) have been proposed as performance indicators, but varying complexity in case mix among endoscopists may potentially affect validity. The study aims to explore the effect of adjusting for case mix on individual endoscopist performance by calculating case mix-adjusted performance estimates (cmCIR and cmPDR) and comparing them to overall performance estimates (oCIR and oPDR). The study also provides an R program for case mix analysis.

Methods

Logistic regression associated endoscopist, colonoscopy indication, patient age and patient gender with the binary outcomes of cecum intubation and polyp detection. Case mix-adjusted performance indicators were calculated for each endoscopist based on logistic regression and bootstraps. Endoscopists were ranked from best to worst by overall and case mix-adjusted performance estimates, and differences were evaluated using percentage points(pp) and rank changes.

Results

The dataset consisted of 7376 colonoscopies performed by 47 endoscopists. The maximum rank change for an endoscopist comparing oCIR and cmCIR was eight positions, interquartile range (IQR 1–3). The maximum change in CIR was 1.95 percentage point (pp) (IQR 0.27–0.86). The maximum rank change in the oPDR versus cmPDR analysis was 17 positions (IQR 1.5–8.5). The maximum change in PDR was 11.21 pp (IQR 2.05–6.70). Three endoscopists improved their performance from significantly inferior to within the 95% confidence interval (CI) range of performance targets using case mix-adjusted estimates.

Conclusions

The majority of endoscopists were unaffected by adjustment for case mix, but a few unfortunate endoscopists had an unfavourable case mix that could invite incorrect suspicion of inferior performance.

Keywords:

• Colonoscopy
• performance monitoring
• cecum intubation rate
• polyp detection rate
• adenoma detection rate

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.