Anti-TNF treatment in Crohn's disease and risk of bowel resection-a population based cohort study

Background: TNF inhibitors (TNFi) have been shown to reduce the need for surgery in Crohn's disease, but few studies have examined their effect beyond the first year of treatment. Aim: To conduct a register-based observational cohort study in Sweden 2006-2014 to investigate the risk of bowel resection in bowel surgery naive TNFi-treated Crohn's disease patients and whether patients on TNFi >= 12 months are less likely to undergo bowel resection than patients discontinuing treatment before 12 months. Methods: We identified all individuals in Sweden with Crohn's disease through the Swedish National Patient Register 1987-2014 and evaluated the incidence of bowel resection after first ever dispensation of adalimumab or infliximab from 2006 and up to 7 years follow-up. Results: We identified 1856 Crohn's disease patients who had received TNFi. Among these patients, 90% treatment retention was observed at 6 months after start of TNFi and 65% remained on the drug after 12 months. The cumulative rates of surgery in Crohn's disease patients exposed to TNFi years 1-7 were 7%, 13%, 17%, 20%, 23%, 25% and 28%. Rates of bowel resection were similar between patients with TNFi survival < 12 months and >= 12 months respectively (P=.27). No predictors (eg, sex, age, extension or duration of disease) for bowel resection were identified. Conclusions: The risk of bowel resection after start of anti-TNF treatment is higher in regular health care than in published RCTs. Patients on sustained TNFi treatment beyond 12 months have bowel resection rates similar to those who discontinue TNFi treatment earlier.