Differences in Urinary Stone Composition according to Body Habitus.
OBJECTIVE
We analyzed differences in urinary stone composition according to body mass index (BMI).


METHODS
Between January 2007 and December 2010, 505 ureteral or renal stones were collected from 505 patients who underwent surgical intervention. Data on patient age, gender, BMI, urinary pH, and stone composition were collected.


RESULTS
The patients' mean age was 49.2 years (range, 20 to 83 years). Of the 505 patients, 196 (38.7%) had calcium oxalate (CO) stones, 172 (33.9%) had mixed calcium oxalate and calcium phosphate (COP) stones, 72 (14.2%) had calcium phosphate (CP) stones, 50 (9.8%) had uric acid (UA) stones, and 15 (2.9%) had struvite stones. We excluded struvite stones in the statistical analysis because of the small number of patients; a total of 490 patients were included in this study. In the multinomial logistic regression analysis, obesity was found to be associated with UA stones compared with COP stones (odds ratio [OR] 3.488; 95% confidence interval [CI] 1.732-7.025; p<0.001) and CP stones (OR 2.765; 95% CI 1.222-6.259; p=0.015). Similar results were observed for CO stones compared with COP stones (OR 2.682; 95% CI 1.727-4.164; p<0.001) and CP stones (OR 2.126; 95% CI 1.176-3.843; p<0.013).


CONCLUSIONS
Obesity was associated with UA and CO stones compared with the occurrence of COP and CP stones.
Department of Urology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
Ji Yun
JY
Jeong
Seung Whan
SW
Doo
Won Jae
WJ
Yang
Kwang Woo
KW
Lee
Jun Mo
JM
Kim