Crohn's disease but not ulcerative colitis elevated risk of end-stage renal disease and mortality: A Taiwan retrospective cohort study

Inflammatory bowel disease (IBD) is an autoinflammatory disease which may affect extraintestinal organs, including kidney. However, rare research showed that patients with IBD have higher risk of end-stage renal disease (ESRD). Furthermore, lack of studies compared the potential risk of ESRD and mortality among patients with ulcerative colitis (UC) and Crohn disease (CD). We conducted a nationwide cohort study using the National Health Insurance database in Taiwan, from January 2008 to December 2018. A total of 3204 patients diagnosed with IBD were enrolled. IBD cases were identified through the presence of a catastrophic illness certificate, including CD and UC. The study outcomes were the incidence of ESRD and mortality. ESRD diagnosis required a serious illness certificate and was identified using the corresponding ICD-10-CM codes. Mortality was recorded in the Taiwan Death Registry linked with the National Health Insurance database, Cox proportional hazards models were used to estimate the risk factors for ESRD and mortality among IBD patients. CD patients had a significantly higher risk of ESRD (adjust hazard ratio: 2.32, 95% confidence interval: 1.28-4.18) and mortality (adjust hazard ratio: 1.80, 95% confidence interval: 1.37-2.35) compared to healthy individuals. UC patients showed no difference in the risk of ESRD compared to healthy individuals. Instead, among IBD patients, UC poses a relatively lower risk for ESRD compared to other factors like age and other comorbidities. Elevated risk of ESRD and mortality was only noted in patients with CD but not UC. Surprisingly, UC patients had lower risk of ESRD and mortality than CD patients. These findings highlight distinctive patterns of risk associated with CD and UC, emphasizing the importance of considering disease subtype when assessing outcomes such as ESRD and mortality.