Abstract
Background To address mismatch between routine endoscopy capacity and demand, centers often
implement initiatives to increase capacity, such as weekend working or using locums/agency
staff (insourcing). However, there are concerns that such initiatives may negatively
impact quality. We investigated polyp detection for weekend vs. weekday and insourced
vs. standard procedures using data from the UK National Endoscopy Database.
Methods We conducted a national, retrospective, cross-sectional study of diagnostic colonoscopies
performed during 01/01–04/04/2019. The primary outcome was mean number of polyps (MNP)
and the secondary outcome was polyp detection rate (PDR). Multi-level mixed-effect
regression, fitting endoscopist as a random effect, was used to examine associations
between procedure day (weekend/weekday) and type (insourced/standard) and these outcomes,
adjusting for patient age, sex, and indication.
Results 92 879 colonoscopies (weekends: 19 977 [21.5 %]; insourced: 9909 [10.7 %]) were performed
by 2496 endoscopists. For weekend colonoscopies, patients were less often male or
undergoing screening-related procedures; for insourced colonoscopies, patients were
younger and less often undergoing screening-related procedures (all P < 0.05). Fully
adjusted MNP was significantly lower for weekend vs. weekday (incidence rate ratio
[IRR] 0.86 [95 %CI 0.83–0.89]) and for insourced vs. standard procedures (IRR 0.91
[95 %CI 0.87–0.95]). MNP was highest for weekday standard procedures and lowest for
weekend insourced procedures; there was no interaction between procedure day and type.
Similar associations were found for PDR.
Conclusions Strategies to increase colonoscopy capacity may negatively impact polyp detection
and should be monitored for quality. Reasons for this unwarranted variation require
investigation.
