Increasing Incidence of Pouchitis Between 1996 and 2018: A Population-Based Danish Cohort Study

Current knowledge regarding the epidemiology of pouchitis is based on highly selected, mostly single-center, patient cohorts. Our objective was to prospectively determine the population-based incidence of pouchitis in patients with ulcerative colitis in the first 2 years after ileal pouch–anal anastomosis and analyze time trends of the incidence of pouchitis. Using national registries, we established a population-based cohort of all Danish patients undergoing proctocolectomy with ileal pouch–anal anastomosis for ulcerative colitis between 1996 and 2018. The primary outcome was the development of pouchitis within the first 2 years after surgery, evaluated by time period. We used Kaplan–Meier and Cox proportional hazard modeling to evaluate the time to development of pouchitis. Overall, 1664 patients underwent an ileal pouch–anal anastomosis. The cumulative incidence of pouchitis in the 2 years after ileal pouch–anal anastomosis increased throughout the study period, from 40% in the period from 1996 to 2000 (95% CI, 35%–46%) to 55% in the period from 2015 to 2018 (95% CI, 48%–63%). Patients undergoing surgery between 2015 and 2018 also showed an increased risk of pouchitis compared with the earliest study period (1996–2000) after adjusting for sex, age, and socioeconomic status (hazard ratio, 1.57; 95% CI, 1.20–2.05). This population-based study showed a 15% absolute and 38% relative increase in the incidence of pouchitis among patients undergoing surgery between 1996 and 2018, with the greatest cumulative incidence of pouchitis shown in the most recent era (2015–2018). The striking increase in the incidence of pouchitis highlights the need for further research into causes and prevention of pouchitis. [Display omitted]