Risk of Urolithiasis in Patients With Inflammatory Bowel Disease: A Nationwide Danish Cohort Study 1977-2018

Background and aims: Patients with inflammatory bowel disease (IBD) are suggested to be at increased risk of urolithiasis, but the magnitude of risk and the impact of medical and surgical treatment on this risk remain unknown. We therefore aimed to determine overall and treatment-related risk of urolithiasis in patients with IBD in a nationwide population-based cohort study.

Methods: Using national registers, we identified all patients with IBD and all cases of urolithiasis in Denmark during 1977-2018. We obtained information on all IBD medications and surgical procedures during 1995-2018. IBD cases were matched 1:10 on age and sex to non-IBD individuals.

Results: In total, 2,549 (3%) of 75,236 IBD patients and 11,258 (2%) of 767,403 non-IBD individuals developed urolithiasis, resulting in a 2-fold increased risk of urolithiasis (HR, 2.27; 95% CI, 2.17-2.38) in patients with IBD. The patients were also at increased risk of repetitive urolithiasis events (RR, 1.09; 95% CI: 1.04-1.15) and had increased risk of urolithiasis prior to IBD diagnosis (OR, 1.42; 95% CI: 1.34-1.50). After IBD diagnosis, risk of urolithiasis was associated with anti-TNF therapy and surgery.

Conclusion: Patients with IBD had a 2-fold increased risk of urolithiasis after IBD diagnosis and a 42% increased risk prior to IBD diagnosis. Risk was increased in anti-TNF exposed patients, and after surgery, suggesting that IBD severity per se and surgery, with altered intestinal absorption, increase risk of urolithiasis. Since stone formation is associated with adverse outcomes including sepsis, subpopulations of IBD patients, especially those undergoing strong immunosuppression might benefit from additional urolithiasis screening.