High-quality colonoscopy depends on adequate training. This study aimed to evaluate the impact of a standardized simulator-based colonoscopy training program on low- to moderately experienced gastroenterologists’ self-reported confidence, navigation comfort, polyp-detection proficiency, familiarity with quality indicators, and perceived diagnostic and therapeutic challenges three months after the training.

This pre–post study enrolled 218 participants from 13 countries with low to moderate colonoscopy experience. All attended a standardized two-day training course combining lectures with hands-on practice on the Mikoto simulator (R ZERO Inc., Japan) across four difficulty stations (Easy, Standard, Advanced 1, Advanced 2) simulating increasing difficulty and realistic tasks such as cecal intubation and loop management. Pre-course and three-month post-course surveys assessed self-reported colonoscopy confidence, navigation comfort, polyp-detection proficiency, familiarity with quality indicators, and perceived diagnostic and therapeutic challenges. All self-reported competencies were rated on a 3-point scale (1 = low, 2 = moderate, 3 = high). Paired analyses were restricted to the 153 participants (70.2%) who completed both surveys. Attrition bias was evaluated by comparing baseline scores between responders (n = 153) and non-responders (n = 65). Ordinal outcomes were analyzed using the Wilcoxon signed-rank test and binary challenge variables using McNemar’s test. Effect-modification analyses were performed according to baseline colonoscopy volume and prior endoscopy training. Statistical significance was set at p < 0.05.

All self-reported competencies increased significantly after training. Confidence scores shifted upward, with the median remaining at 2 but the distribution moving from (IQR 1–2) to (IQR 2–3), navigation comfort from 1 (IQR 1–2) to 2 (IQR 1–3), polyp-detection proficiency from 2 (IQR 2–3) to 3 (IQR 3–3), and familiarity with quality indicators from 2 (IQR 1–3) to 3 (IQR 3–3) (all p < 0.0001). Frequency-shift analyses showed upward transitions: 47.7% improved in confidence, 44.4% in navigation, 36.6% in polyp-detection proficiency, and 51.6% in quality-indicator familiarity, with rare declines (2.6%). Self-reported diagnostic challenges decreased from 80.9% to 38.8%, and therapeutic challenges from 92.1% to 63.2% (p < 0.0001). Attrition bias assessment showed no meaningful baseline differences between responders and non-responders. Participants who performed <50 prior colonoscopies showed greater improvement in confidence than those who performed ≥51 (p = 0.0003), and those without prior formal training showed greater improvement than trained participants (p = 0.0035). Navigation changes were not significantly different across subgroups.

Participation in a standardized simulation-based colonoscopy training course was associated with higher self-reported confidence, perceived procedural proficiency, and fewer perceived diagnostic and therapeutic challenges three months later. Greater gains among less experienced and untrained participants support the value of structured simulation in early endoscopy training.