P243 Colectomy rates in ulcerative colitis are low and decreasing: Ten-year follow-up data from the Swiss IBD cohort study

Previous population-based studies in patients with ulcerative colitis (UC) revealed variable colectomy rates and colectomy-associated risk factors. Over the last two decades, a decrease in colectomy rates was observed. We assessed risk factors and colectomy rates over time in UC in the Swiss Inflammatory Bowel Disease Cohort Study (SIBDCS). Prospectively collected SIBDCS data, including disease history, baseline characteristics at enrolment, and course of disease, were retrospectively analysed. Cumulative and adjusted annual colectomy rates were calculated. Among 1245 UC patients analysed (54.6% male), 114 (9.2%) underwent colectomy. We observed 5-, 10-, 15- and 20-year cumulative colectomy rates after diagnosis of 4.1%, 6.4%, 10.4% and 14.4%, respectively. Male sex (odds ratio OR 1.54; p = 0.035), pancolitis at diagnosis (compared with left-sided colitis: OR 0.39; p < 0.002, and proctitis: OR 0.25; p < 0.001), younger age at diagnosis (OR 0.98 per year; p = 0.006) and The presence of extraintestinal manifestations (EIM; OR 2.30; p < 0.001) were risk factors for undergoing colectomy (family history not significant. OR 1.69; p = 0.060). We did not observe a significant protective effect of smoking on colectomy risk (OR 0.64; p = 0.106). The majority of colectomies were performed within first 10 years of disease onset with a rapidly decreasing colectomy rate after 15 years. The observed survival rate of colectomy-free proportion over time according to disease duration is depicted in a Kaplan–Meier survival estimate and a 95% confidence interval (CI = confidence interval). In patients diagnosed after 2003, colectomy was performed much earlier during individual’s disease course. Nevertheless, we found a significant decrease in yearly colectomy rates over time after 2010 The observed incidence rate of colectomy over time is depicted in conjunction with a crude, un-adjusted predicted yearly rate (CI = confidence interval). Male sex, presence of pancolitis, younger age at diagnosis, and presence of EIMs are risk factors for undergoing colectomy. Crude and adjusted colectomy rates in Swiss UC patients are lower than those reported previously in the literature and decreased over time after 2005. Our data indicate that the highest colectomy rate is observed in the first years after UC diagnosis (a peak incidence after 10 years) followed by a considerable decrease in risk of colectomy in the long run.