A specific phenotype of pouchitis was associated with worst prognosis in patients with ulcerative colitis according to Chicago classification

Background The impact of different pouch phenotypes on long-term functional outcomes and quality of life (QoL) remains unclear. Our aim is to investigate the association between endoscopic pouchitis phenotypes and patients' long-term prognosis by assessing pouch function and QoL. Methods Pouchitis was classified into distinct phenotypes according to the Chicago Classification. Pouch function was assessed using the Pouch Functional Score (PFS), and QoL was evaluated using the Cleveland Global Quality of Life (CGQL) score. Results A total of 252 patients were enrolled in the study, with 78 patients diagnosed with pouchitis. According to the Chicago classification, 42 of these pouchitis patients exhibited an endoscopic phenotype characterized by a combination of diffuse inflammation of the pouch body, inlet involvement, and cuffitis, referred to as the Diffuse-Inlet-Cuffitis phenotype. Patients with pouchitis of the Diffuse-Inlet-Cuffitis phenotype showed significantly higher PFS (11.5 vs 5.5, p = 0.013) and lower CGQL scores (0.67 vs 0.7, p = 0.029) compared to those with other pouch phenotypes. Independent risk factors for this severe phenotype were identified as preoperative disease duration (OR = 1.062, 95% CI: 1.006–1.122, p = 0.030) and disease extent E3 (OR = 2.836, 95% CI: 1.052–7.644, p = 0.036). Conclusions Our study suggested that pouchitis with the Diffuse-Inlet-Cuffitis endoscopic phenotype is common and seriously impairs the long-term prognosis in patients with UC after IPAA. The finding will be beneficial to the stratified management of patients with pouchitis.