Introduction: The London classification provides standardization for characterization of disorders of anorectal function, although prevalences and clinical impact of these disorders are unclear.
Methods: An international research consortium was established, including five specialist centers. Prospective data were collected in consecutive adults referred for refractory chronic constipation (CC), fecal incontinence (FI) or coexistent CC/FI over 18 months. Patients completed a standardized clinical questionnaire and underwent anorectal physiology tests which were performed and interpreted using uniform methodology. The prevalence of the London classification was compared between symptom groups (CC, FI and coexistent CC/FI), equipment types, and sites. Clinical impact was assessed using Cleveland Clinic constipation and St. Marks incontinence scores.
Results: Of 1,012 included patients (85.6% women), 30.5% had self-reported CC, 33.2% had FI, and 36.3% had coexistent CC/FI. Rectoanal areflexia was uncommon (3.1%). Disorders of anal tone/contractility (CC: 45.0%; FI: 68.5%; coexistent CC/FI: 63.8%; p<0.0001), and disorders of rectal sensation (major findings: rectal hyposensitivity, CC: 10.0%; FI: 5.0%; coexistent CC/FI: 11.1%; p=0.018; rectal hypersensitivity, CC: 3.8%; FI: 9.0%; coexistent CC/FI: 4.9%; p=0.025) varied between symptom groups and were associated with symptom severity. Most disorders of rectoanal coordination were found in similar proportions across symptom groups and were not associated with severity of CC (median Cleveland Clinic constipation score 10-14 in all groups). Prevalences of some disorders differed between equipment types (specifically balloon expulsion test).
Discussion: This prospective multicenter study provides information on the prevalence and clinical impact of the London classification, and will guide refinement of the current London classification.
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