Reply letter regarding concerning issues in evaluating the inter-rater reliability. Comment on 'risk factors for underestimation of patient pain in outpatient colonoscopy by ryhlander et al.' by Yu et al.

Summary: The estimation of patient pain during colonoscopy by endoscopists and endoscopy assistants is often inaccurate. It is important for endoscopists to pay specific attention to subgroups of patients, such as male gender and normal BMI, as there seems to be a higher risk of underestimation of moderate-severe pain in these patients.