Renal and urological complications in patients with Inflammatory Bowel Disease

Background: Renal and urological manifestations are recognized but understudied extraintestinal features of inflammatory bowel disease (IBD). Our aim was to estimate their prevalence and to identify associated clinical parameters. Methods: This was a retrospective, single-center, observational study, including IBD patients with at least one year of follow-up and documented renal function monitoring. Demographic, clinical, and laboratory data were collected. The primary outcome was the composite outcome of kidney injury acute kidney injury (AKI) and/or chronic kidney disease (CKD) during follow-up. Secondary outcomes included AKI, CKD, and urolithiasis. Associations with independent variables were first assessed using univariate logistic regression; a multivariable model was then constructed for the primary outcome. Results: A total of 660 patients were included in this study 379 (57.4%) male, 368 (56%) Crohn’s disease (CD), 292 (44%) Ulcerative Colitis (UC). The primary outcome occurred in 54 patients (8.3%), 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, male sex (aOR 2.14, 95% CI: 1.06–4.32, p = 0.034), Charlson Index (per 1-point increase, aOR 1.53, 95% CI: 1.26–1.86, p < 0.001) and arterial hypertension (aOR 2.43, 95% CI: 1.20–4.94, p = 0.014). In UC extensive colitis independently predicted renal injury (aOR 2.81, 95% CI: 1.11–7.73, p = 0.035). AKI was associated with older age at IBD diagnosis and increased frequency of disease flares. All secondary outcomes were linked to arterial hypertension and dyslipidemia. Conclusion: Renal and urological complications are relatively common in IBD (8.3% and 7.3% respectively). IBD-related surgery and extensive UC are independent risk factors. Cardiometabolic comorbidities also play a substantial role.