Pain vs Stools: The IBS-C/FC Diagnostic Split
Authors of a scoping review of 27 clinical practice guidelines (CPGs) from 2012 to 2024 found considerable inconsistency in diagnostic criteria for constipation-predominant IBS (IBS-C) and functional constipation (FC). Rome IV was most commonly used (59.3%), followed by Rome III (22.2%). IBS-C guidelines emphasized abdominal pain (71.4%), whereas FC guidelines prioritized spontaneous bowel movement frequency (88.9%). IBS-C CPGs often endorsed positive, symptom-based diagnosis (71.4%) versus far fewer FC CPGs (11.1%). Forty percent of CPGs acknowledged overlap between IBS-C and FC. One guideline proposed a pain threshold (Likert >4) to define “painful constipation.” Regional variation was notable: some Asian-based CPGs highlighted Bristol Stool Form Scale type 3 and abdominal bloating; most CPGs (81.5%) recommended colonoscopy only for alarm features or age criteria. These discrepancies likely skew prevalence estimates, payer policies, and clinical trial eligibility across regions.
Overall, the landscape is fragmented and region-dependent, complicating differential diagnosis and care pathways. The authors call for harmonized criteria that better integrate both pain and constipation domains across IBS-C and FC, and for progress toward objective biomarkers to reduce reliance on symptoms alone. As an interim step, standardized reporting of stool form, pain intensity scales, and symptom duration could improve comparability across settings while biomarker research matures.
Reference: Luo J, To WLW, Xu Q, et al. Clinical practice guidelines for the diagnosis of constipation-predominant irritable bowel syndrome and functional constipation in adults: a scoping review. BMC Gastroenterol. 2025;25(1):234. doi: 10.1186/s12876-025-03774-6.
Carol M. Antequera
DMSc, PA-C