THE PREVALENCE OF DISORDERS OF ANORECTAL FUNCTION ACCORDING TO THE LONDON CLASSIFICATION IN >1000 CONSECUTIVE PATIENTS: A PROSPECTIVE, INTERNATIONAL, MULTICENTRE STUDY FROM THE LOWER GASTROINTESTINAL INTERNATIONAL CONSORTIUM (LOGIC)

Introduction: Clinical and diagnostic assessments of patients with faecal incontinence (FI) and chronic constipation (CC) vary widely. The recent International Anorectal Physiology Working Group (IAPWG) protocol and London classification have provided recommended methods and nomenclature for characterisation of these disorders, though large population studies using this standardised approach have not been performed. Five specialist colorectal and motility centres (UK, France, Mexico, Australia, USA) collaborated in this prospective, international, multicentre study. Aims: (1) Establish an international research collaboration (Lower Gastrointestinal International Consortium [LoGIC]) using the IAPWG protocol and London classification; (2) Describe the prevalence of disorders of anorectal function using the Londonclassification in patients with FI, CC, or coexistent symptoms. Methods: Collaboration and data sharing agreements were implemented to establish the LoGIC group. Prospective, standardised data collection of symptom questionnaires andresults of anorectal tests according to the IAPWG protocol were performed for all adult patients over an 18-month period. Descriptive statistics reported the prevalence of disorders of anorectal function according to the London classification. Results: 1,012 adult patients were included (866 females, 85.6%), presenting with CC (n=309, 30.5%), FI (n=336, 33.2%), or coexistent symptoms (n=367, 36.3%). Demographics and clinical characteristics (Table 1) and prevalence of disorders according to the London Classification (Table 2) are provided. Key findings include: Part I: rectoanal areflexia was very uncommon (3.1%); Part II: disorders of anal tone and contractility were more common in patients with FI (61.9%) or coexistent symptoms (59.7%) compared to patients with CC (44.0%; p<0.01); Part III: 34.8% of patients overall had abnormal balloon expulsion, but only 13.4% had abnormal expulsion combined with a manometric abnormality. Dyssynergia was uncommon (<10% overall) and had a similar prevalence in each of the three symptom subgroups, raising uncertainty over its clinical utility; Part IV: disorders of rectal sensation were specific for symptom subgroups, with rectal hyposensitivity being more prevalent in patients with CC (10% vs. 5% in FI; p=0.02), and rectal hypersensitivity in patients with FI (9% vs. 4% in CC; p=0.01). Conclusion: This initial study from the LoGIC group demonstrates that a prospective, international, multicentre study with standardised data collection in the field of anorectal physiology is feasible and could be expanded globally. Some test results, specifically measurement of anal tone/contractility and rectal sensation, were significantly different between symptom subgroups. These results could guide further refinement of the London classification.