Renal and urological complications in patients with inflammatory bowel disease

Objective Renal and urological manifestations are understudied extraintestinal features of inflammatory bowel disease (IBD). Our aim was to estimate their prevalence and identify associated clinical parameters. Methods This retrospective, single-center, observational study, included IBD patients with at least 1 year of follow-up and documented renal function monitoring. Demographic, clinical, and laboratory data were collected. The primary outcome was renal injury defined as acute kidney injury (AKI), chronic kidney disease (CKD), or both during follow-up. Secondary outcomes were AKI, CKD, and urolithiasis. Associations were assessed using univariate and multivariable logistic regression analyses. Results A total of 660 patients were included [379 (57.4%) male; 368 (56%) had Crohn’s disease and 292 (44%) ulcerative colitis]. The primary outcome occurred in 54 patients (8.2%), AKI in 23 (3.5%), CKD in 35 (5.3%), and urolithiasis in 48 (7.3%). Independent risk factors for renal injury included IBD-related surgery [adjusted odds ratio (aOR): 2.69, 95% confidence interval (CI): 1.25–5.80, P = 0.012], extensive ulcerative colitis (aOR: 2.81, 95% CI: 1.11–7.73, P = 0.035), arterial hypertension (aOR: 2.43, 95% CI: 1.20–4.94, P = 0.014), male sex, and Charlson Comorbidity Index. AKI was associated with older age at IBD diagnosis and a higher frequency of disease flares. In a multivariable model, IBD-related surgery was independently associated with urolithiasis (aOR: 2.20, 95% CI: 1.03–4.70, P = 0.042). Conclusion Renal and urological complications are relatively common in IBD. IBD-related surgery, extensive ulcerative colitis, and cardiometabolic comorbidities are associated with renal injury, while IBD-related surgery is also independently associated with urolithiasis.