<p><strong>BACKGROUND &amp; AIMS: </strong>It is not clear what factors affect risk of chronic kidney disease (CKD) in patients with inflammatory bowel disease (IBD); increased risk has been inconsistently associated with use of 5-aminosalicylates (5-ASAs). We aimed to calculate the relative hazard of CKD among patients with IBD, adjusted for CKD risk factors, and to determine whether IBD medications are associated with change in estimated glomerular filtration rate (eGFR).</p>

<p><strong>METHODS: </strong>We performed a retrospective cohort study of data from The Health Improvement Network. Patients with IBD (n=17,807) were matched for age, sex, and practice to individuals without IBD (n=63,466). The relative hazard of CKD, stages 3 through 5D, in patients with IBD was calculated using a Cox proportional hazards model adjusted for common CKD risk factors. We also evaluated the association of 5-ASAs, azathioprine, and methotrexate with change in eGFR using a longitudinal model.</p>

<p><strong>RESULTS: </strong>After we controlled for risk factors associated with CKD, we found IBD to be associated with development of CKD in patients 16-77 years old. As patient age increased, the adjusted hazard ratio for CKD decreased monotonically, from 7.88 (95% CI, 2.56-24.19) at age 16 to 1.13 (95% CI, 1.01-1.25) at age 77. In the longitudinal analysis, exposure to 5-ASAs or methotrexate was not associated with change in eGFR, whereas azathioprine was associated with a slightly higher eGFR (0.32 mL/min/1.73 m; 95% CI, 0.16-0.48).</p>

<p><strong>CONCLUSIONS: </strong>In a retrospective study of more than 80,000 persons, we found that IBD is associated with increased risk of CKD, and the hazard ratio is highest among younger patients. Commonly used non-biologic therapeutic agents were not associated with lower eGFR.</p>