Risk and predictors of surgery in a newly diagnosed cohort of IBD patients in the biologic era: Results from the EpidemIBD study

Abstract Background The management of inflammatory bowel disease (IBD) has substantially changed in the last decades, both in relation to medical and surgical treatments. Aims Principal: To know the rate of surgery in a newly diagnosed IBD cohort within the first year after diagnosis. Secondary: To describe the type of surgeries and indications in this cohort, and to identify predictive factors for surgery (focused on intestinal resection) in these patients. Methods Prospective, population-based nationwide registry. Adult patients diagnosed with IBD -Crohn’s disease (CD) and ulcerative colitis (UC)- during 2017 in Spain were included and were followed-up for 1 year. Kaplan-Meier curves were used to calculate the rate of surgery. In patients with intestinal resections, only medical treatments before surgery were considered. Predictive factors for surgery were identified by Cox-regression analysis. Results 3,454 patients (1,647 CD and 1,807 UC) were included (table 1). The incidence rate for surgery was significantly higher among CD patients (figure 1). A total of 197 patients (6%) underwent surgery within the first 12 months: 126 (64%) intestinal resections, and 71 (36%) perianal surgeries. Fifty-seven percent of intestinal resections were urgent, and 43% elective. The main indications for intestinal resections were: intestinal obstruction in 37%, abscess/fistula in 27%, perforation/acute abdomen in 25%, and refractoriness to medical treatment in 18% of cases. A total of 174 CD patients (10.6%) underwent surgery ¾61% intestinal resections and 39% perianal. Twenty-three UC patients (1.3%) were operated on; the number of surgeries in UC was too low to identify predictive factors. In CD patients, to have been treated with thiopurines [Hazard ratio (HR)=0.2, 95% confidence interval (CI)=0.1–0.3) was associated with lower likelihood of intestinal resection. Disease behaviour at diagnosis [stricturing vs. inflammatory (HR=6.5, 95%CI=4–10) and fistulising vs. inflammatory (HR=13, 95%CI=9–21)] was associated with the risk of intestinal resection. Biologic treatment was not associated with the likelihood of intestinal resection (figure 2). Conclusion Six percent of IBD patients undergo surgery within the first year of diagnosis, being higher in CD (11%) than in UC (1.3%). Sixty percent of intestinal resections are urgent procedures. The risk of surgery is increased in CD patients with fistulising and stricturing behaviour. Thiopurine, but not biologic treatment, is associated with lower risk of surgery.