A new colonoscopy performance metric may have shown strong associations with existing quality indicators and could offer a more precise way to assess endoscopy performance.
In a study of 92,879 colonoscopies conducted in the United Kingdom between January and April 2019, investigators evaluated polyp detection after adjusting for age, sex, and procedure indication to account for variation in risk profiles.
The new colonoscopy performance metric, the adjusted mean number of polyps per 100 procedures (aMNP), correlated strongly with two established detection metrics: polyp detection rate (PDR) and proximal polypectomy rate (PPR). At the endoscopist level, aMNP correlated with PDR (ρ = 0.834, P < .001) and PPR (ρ = 0.709, P < .001), with similar associations observed at the institutional level.
Hospitals with lower rates of postcolonoscopy colorectal cancer (PCCRC) had significantly higher median aMNP scores. Trusts with PCCRC rates below the median of 6.7% had aMNP scores of 73.9 per 100 procedures compared with 67.0 in those with higher rates (P = .047).
Institutional accreditation scores further supported the metric. Endoscopy units with passing Global Rating Scale (GRS) grades (A or B) had higher median aMNP scores than those with failing grades (63.5 vs 55.2, P < .001). Similarly, JAG-accredited units had higher adjusted polyp counts than nonaccredited ones.
“aMNP addresses many limitations of [the adenoma detection rate] (ADR), adjusts for warranted variation in detection, and hence may improve audit and feedback engagement. We propose it as a candidate gold standard [key performance indicator] for reporting endoscopy quality,” said lead study author Jamie Catlow, of Newcastle Upon Tyne Hospitals National Health Service Foundation Trust, and colleagues.
Unlike the ADR, which includes only the first adenoma and excludes serrated polyps, the aMNP includes all polyp types and does not rely on histology. This distinction is critical, as serrated polyps are often subtle, located in the proximal colon, and associated with increased cancer risk.
Age and sex were important predictors of polyp detection. Patients aged 70 years and older had more than three times the detection rate compared with those under 40 (incidence rate ratio [IRR] = 3.05, 95% confidence interval [CI] = 2.90–3.20). Male patients also had higher detection rates than female patients (IRR = 1.47, 95% CI = 1.44–1.51). Screening procedures and those for prior polyps yielded the highest detection rates.
The investigators calculated aMNP by estimating the expected number of polyps for each procedure based on case mix, then adjusting observed counts using a national average, scaled to 100 procedures.
The metric could be integrated into centralized databases, eliminating the need for manual histology audits and supporting consistent benchmarking of colonoscopy quality nationwide.
The investigators concluded that aMNP may serve as a future standard for evaluating detection performance across clinicians and institutions.
The authors reported no competing interests.
Source: BMJ Open Gastroenterology
