P1142 Antibiotic use in the twelve months prior to ileal pouch-anal anastomosis increases the risk for pouchitis: A population-based Danish cohort study

Abstract

Abstract Background Pouchitis is the most common complication after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC), however clinical and environmental risk factors for pouchitis remain poorly understood. We explored the relationship between specific clinical factors and the incidence of pouchitis. Methods We established a population-based cohort of all adult persons in Denmark undergoing proctocolectomy with IPAA for UC between January 1, 1996 and May 31, 2020. We used Cox Proportional Hazard modeling and logistic regression to assess the impact of antibiotic and non-steroidal anti-inflammatory drug (NSAID) exposure and appendectomy on the primary outcome of diagnosis of acute pouchitis in the first 2 years after IPAA surgery. A 2-year time window was utilized given the clinical relevance of early pouchitis and to mirror prior studies in both administrative claims and the Danish health registers. Results Among 1,616 eligible patients, 738 (46%) developed pouchitis in the first 2 years after IPAA. Among all patients undergoing IPAA surgery for UC, 51% were prescribed antibiotics in the 12 months prior to the index date and 17% were prescribed NSAIDs in the 12 months prior to the index date. In Kaplan-Meier analyses, those persons who were prescribed antibiotics in the 12 months prior to the final stage of IPAA surgery were significantly more likely to develop pouchitis in the 2 years after the index date when compared to patients who were not prescribed antibiotics (p<0.001, Figure 1B). Additionally, male patients demonstrated a decreased risk for pouchitis in the first 2 years after the index date when compared to female patients (p=0.014, Figure 1A). Antibiotic exposure in the 12 months prior to IPAA was associated with an increased risk of pouchitis (adjusted Hazard Ratio [aHR] 1.40, 95% CI 1.21-1.62) after adjusting for year of surgery and sex (Table 1). In a secondary analysis, compared to persons without any antibiotic prescriptions in the 12 months prior to IPAA, the risk of pouchitis was increased in those with 1 or 2 courses of antibiotics in that period (aHR 1.29, 95% CI 1.10-1.51) and 3 or more courses (aHR 1.79, 95% CI 1.43-2.23, Figure 1C). NSAID exposure in the 12 months prior to IPAA and appendectomy were not associated with risk of acute pouchitis (p=0.201 and p=0.865 respectively). Conclusion In this population-based cohort study, we demonstrated that antibiotic exposure in the 12 months prior to IPAA is associated with an increased risk of acute pouchitis. Future prospective studies may isolate specific microbial changes in at-risk patients to drive earlier interventions.