Risk Factors for Urolithiais in Patients with Ileal Conduit Urinary Diversion

Kim, Tae Hwan; Woo, Seung Hyo; Lee, Young Suk; Lee, Hyung Lae; Lee, Sang Cheol; Kim, Wun Jae

Abstract

PURPOSE: The present study was performed to assess the risk factors for urolithiasis in patients receiving ileal conduit urinary diversion due to a certain underlying etiology.
MATERIALS AND METHODS
This study included 43 patients (35 males and 8 females), who had undergone ileal conduit urinary diversion with a post-operative duration of at least 6 months, and 54 age-matched normal controls. Urine samples (24-hour) were collected on an outpatient basis without any dietary restriction when the patients were free of urinary tract infection or antibiotics medication. The urinary analytes, comprising of the urine volume, sodium, phosphorus, uric acid, creatinine, calcium, magnesium, oxalate and citrate, were investigated. These data were compared with the original values, and the values adjusted according to the creatinine level for both sexes.
RESULTS
Not all the serum analytes significantly differed between the patients and controls. In the 35 male patients, the mean urinary excretion of oxalate was significantly greater than in the control group, which was converse to that of the citrate and uric acid (p=0.001, p<0.001 and p=0.001, respectively). Unexpectedly, the urinary excretion of calcium in the male patients was lower than in the controls (p<0.001), resulting in a significant decrease in the ratio of calcium to oxalate (p<0.001). Among the urinary analytes, the excretions of sodium, phosphorus, uric acid, citrate and oxalate were significantly correlated with that of urinary creatinine. The excretions of oxalate and citrate were different when adjusted according to the urinary creatinine excretion between the male patients and the controls. In the 8 female patients, decreases in the excretions of magnesium and citrate were observed compared to the controls (p=0.007, p=0.030).
CONCLUSIONS
Our study indicated that ileal conduit urinary diversion causes increased excretion of urinary oxalate, leading to a decreased calcium to oxalate ratio and excretion of citrate as major metabolic alterations due to urolithiasis, although the excretions of urinary calcium and magnesium may play some role.