Background High-quality colonoscopy is crucial to ensure complete mucosal visualisation and to maximise detection of pathology. Previous audits showing variable quality have prompted national and international colonoscopy improvement programmes, including the development of quality assurance standards and key performance indicators (KPIs). The most widely used marker of mucosal visualisation is the adenoma detection rate (ADR), however, histological confirmation is required to calculate this. We explored the relationship between core colonoscopy KPIs.

Methods Data were collected from colonoscopists in eight hospitals in North East England over a 6-month period, as part of a quality improvement study. Procedural information was collected including number of colonoscopies, caecal intubation rate (CIR), ADR and polyp detection rate (PDR). Associations between KPIs and colonoscopy performance were analysed.

Results 9265 colonoscopies performed by 118 endoscopists were included. Mean ADR and PDR per endoscopist were 16.6% (range 0–36.3, SD 7.4) and 27.2% (range 0–57.5, SD 9.3), respectively. Mean number of colonoscopies conducted in 6 months was 78.5 (range 4–334, SD 61). Mean CIR was 91.2% (range 55.5–100, SD 6.6). Total number of colonoscopies and ADR>15% were significantly associated (p=0.04). Undertaking fewer colonoscopies and using hyoscine butylbromide less frequently was significantly associated with ADR<15%. CIR, endoscopist grade, % male patients, mean patient age and CIR were not significantly related to ADR<15%. In adjusted analyses, factors which affected ADR were PDR and mean patient age.

Conclusion Colonoscopists who perform fewer than the nationally stipulated minimum of 100 procedures per year had significantly lower ADRs. This study demonstrates that PDR can be used as a marker of ADR; providing age is also considered.