The Risk of Type 2 Diabetes in Patients With Inflammatory Bowel Disease After Bowel Resections: A Nationwide Cohort Study

BACKGROUND AND AIMS: Patients with inflammatory bowel disease (IBD) are at increased risk of type 2 diabetes (T2D), but the underlying mechanisms remain elusive. We aimed to determine the impact of small and large bowel resections on the risk of developing T2D in patients with IBD. METHODS: We conducted a nationwide, prospective study of all IBD patients undergoing small bowel resection (Crohn's disease [CD]) and large bowel resection (CD and ulcerative colitis [UC]) in Denmark (1996-2018). Each patient was matched with up to 5 patients with IBD and no history of bowel resection. We used Cox proportional hazards regression models to estimate adjusted hazard ratios (aHRs) of T2D. RESULTS: We included 2469 patients with CD and small bowel resection, 1361 patients with CD and large bowel resection, and 3787 patients with UC and large bowel resection. Small bowel resection in CD patients was associated with lower risk of T2D (aHR 0.65, 95% CI, 0.44-0.92), compared with matched patients with CD and no bowel resection. Large bowel resection in patients with CD or UC was associated with aHRs of 0.95 (95% CI, 0.67-1.31) and 1.25 (95% CI, 1.03-1.51), respectively, compared with matched patients with CD or UC and no bowel resection. CONCLUSION: Patients with CD and small bowel resection have a lower risk of T2D, whereas patients with UC and large bowel resection have a higher risk of T2D, compared with patients with IBD and no bowel resection history. The underlying mechanisms remain to be explored.