Urolithiasis in complicated inflammatory bowel disease: a comprehensive analysis of urine profile and stone composition.

Purpose: To evaluate the impact of extensive surgery on urine profile, serum exams and stone composition of complicated IBD patients.

Methods: Patients with IBD and a history of total proctocolectomy (TPC) with fecal diversion (end ileostomy or ileal pouch anal anastomosis-IPAA) were selected. Only patients with at least one complete 24-h urine profile were included. A case-control study was performed selecting patients with kidney stone disease in a random way who had also at least on complete 24-h urine profile. Case and controls were matched for age, gender, and body mass index (BMI). Groups were compared to urine profile, serum exams and stone composition.

Results: Sixty-eight patients were enrolled in this study, 34 patients with IBD who underwent TPC and had diagnosis of kidney stones and 34 matched patients with only kidney stones. IBD patients had a significantly lower urine volume, urine citrate and urine sodium. Regarding serum exams, only serum bicarbonate was statistically significant lower. In both groups, calcium oxalate stone was the most common.

Conclusion: Patients with IBD with TPC and kidney stones have a low urine volume and low urine citrate as main risk factors for kidney stone formation. As seen in the general population, calcium oxalate is the most common stone composition.