Is painless colonoscopy associated with trainee learning? A single-center study of insertion speed and adenoma...

To compare the learning curves of cecal intubation time and adenoma detection rate (ADR) between painless (sedated) and conventional (non-sedated) colonoscopy performed by trainees.

This single-center retrospective cohort comprised the first 1,769 colonoscopies performed by eight trainees without prior colonoscopy experience, grouped by sedation status into a conventional group (n = 852) and a painless group (n = 917). Mixed-effects models characterized the learning trajectories of cecal intubation time and ADR, and an extended model allowing a random case-order slope tested individual heterogeneity. The caseload to independent cecal intubation competency was estimated with a rolling 20-procedure success-rate threshold and Bernoulli cumulative sum (CUSUM) analysis.

Cecal intubation time was shorter in the painless group (median 6 vs. 10 min, P < 0.001). The case-order × procedure-type interaction fell from -0.113/SD (P < 0.001) in the random-intercept model to -0.027/SD (P = 0.589) in the random-slope model and was not significant under an exact trainee-level permutation test (exact P = 0.23); the overall shortening of intubation time with painless colonoscopy was robust to all specifications. Sedation status, calendar era, and scope model were highly correlated at the trainee level (r = 0.92), precluding separation of their independent effects. The overall ADR was 13.0% and declined early with experience (odds ratio 0.80/SD, P = 0.002). Fewer procedures were required to reach independent cecal intubation competency in the painless group (rolling threshold 37 vs. 114; CUSUM 107 vs. 134); however, this difference could not be separated from calendar era and equipment upgrades.

Intubation time was shorter overall under sedation, but the faster learning of the painless group vanished once individual heterogeneity was modeled, and ADR showed no robust improvement. Sedation, era, and equipment were confounded; no causal inference regarding the effect of sedation on learning can be drawn from these data, and prospective confirmation is required. Intubation speed alone should not serve as a benchmark of overall colonoscopy competence.