LAUSR

BACKGROUND Non-modifiable patient and endoscopy characteristics might influence colonoscopy performance. Differences in these so-called case-mix factors are likely to exist between endoscopy centres. This study aims to examine the importance of case-mix adjustment when comparing performance between endoscopy centres. METHODS Prospectively collected data recorded in the Dutch national colonoscopy registry between 2016-2019 were retrospectively analyzed. Performance on cecal intubation rate (CIR) and adequate bowel preparation rate (ABPR) were studied. Additionally, polyp detection rate (PDR) was studied in fecal immunochemical test (FIT)-positive screening colonoscopies. Variation in case-mix factors between endoscopy centres and expected outcomes for each performance measure were calculated per endoscopy centre, based on their case-mix factors (sex, age, ASA score, indication), using multivariable logistic regression. RESULTS In total, 363,840 colonoscopies were included from 51 endoscopy centres. The mean percentages per endoscopy centre were significantly different for age > 65 years, male patients, ASA > III and diagnostic colonoscopies (all p < 0.001). In the FIT-positive screening population, significant differences were observed per endoscopy centre for age > 65 years, male patients and ASA > III (all p value < 0.001). The expected CIR, ABPR and PDR ranged from 95.0% to 96.9%, from 93.6% to 96.4% and from 76.2% to 79.1%, respectively. Age, sex, ASA classification and indication were significant case-mix factors for CIR and ABPR. In the FIT-positive screening population, age, sex and ASA classification were significant case-mix factors for PDR. CONCLUSION Our findings emphasize that when comparing colonoscopy performance measures between endoscopy centres, case-mix adjustment should be considered.