Physician-patient discordance in Bristol stool scale classification and overall IBS burden assessment

Background: The Bristol Stool Form Scale (BSFS) is widely used to assess stool consistency and subtype irritable bowel syndrome (IBS). Methods: Post-hoc analysis of a randomized trial comparing patient self-reported BSFS with physician-assessed BSFS. Baseline symptom severity and quality-of-life questionnaires were also collected. Results: Agreement was poor across the 7-point scale (κ=-0.01, p=0.77) and after collapsing into three categories (κ=0.04, p=0.46), with concordance in only 18/64 cases (28%). Symptom severity and quality-of-life scores were similar between concordant and discordant groups. Discussion: Patient-reported BSFS may not reliably reflect stool consistency or overall IBS burden, suggesting caution when using BSFS alone for monitoring or subtyping IBS.