Colectomy rates in ulcerative colitis are low and decreasing: 10-year follow-up data from the Swiss IBD cohort study

Objectives: Previous population-based studies in patients with ulcerative colitis [UC] revealed variable colectomy rates and colectomy-associated risk factors. Over the past 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]. Methods: 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. Results: 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% of patients, respectively. Male sex (odds ratio [OR] 1.54; p = 0.035), pancolitis at diagnosis [OR = 2.16; p = 0.005], younger age at diagnosis [OR 0.89 per 5 years of age; p = 0.006] and presence of extraintestinal manifestations [EIM] [OR 2.30; p < 0.001] were risk factors for undergoing colectomy. 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. In patients diagnosed after 2003, colectomy was performed much earlier during and individual's disease course. Nevertheless, we found a significantly decreasing trend in yearly colectomy rates over time after 2005. Conclusions: Crude and adjusted colectomy rates in Swiss UC patients were lower than those reported previously in the literature, and decreased over time.