Prospective evaluation of 24-hour urine profiles following bariatric surgery in a modern comprehensive care bariatric clinic.
OBJECTIVE
To prospectively examine the effect of modern bariatric surgery on 24-hour urine parameters in a comprehensive care bariatric practice (CCBP).


METHODS
47 consecutive patients in our CCBP underwent serum and 24-hour urine analysis pre-operatively, and 30 returned at 12 months for repeat testing. Paired comparisons for serum metabolite and 24-hour urine measures were performed using a Wilcoxon signed-rank test for continuous variables and McNemar's test for categorical variables. Statistical tests were two-sided, with threshold of significance set at p = 0.05.


RESULTS
All 30 patients with pre-operative and 12-month follow-up analysis were free of stone events. 20 (67%) had Roux-en-Y gastric bypass (RYGB), 6 (20%) had laparoscopic gastric banding (LGB), and 4 (13%)h ad laparoscopic sleeve gastrectomy (LSG). 24-hour urinary parameters were available for 27 patients. Median urine oxalate (mmol) was 0.29 pre-operatively and 0.21 at 12 months (p = 0.048). Median urine calcium (mg) was 143 pre-operatively and 180 at 12 months (p = 0.11). Median citrate excretion was 527 pre-operatively and 782 at 12 months (p = 0.22). Median serum creatinine was 0.7 pre-operatively and 0.8 at 12 months (p < 0.001). These trends were preserved with the exclusion of LGB and LSG patients.


CONCLUSIONS
Modern bariatric surgery (RYGB, LGB, and LSG) as part of a CCBP can still demonstrate alterations of select urinary parameters (particularly oxalate and citrate) in select patients associated with an increased risk of urolithiasis at 1 year follow-up.
Ryan
R
Hutchinson
Alexander S
AS
Parker
Michelle
M
Arnold
Steven P
SP
Bowers
William E
WE
Haley
Nancy
N
Diehl
Ronald
R
Stone
Scott A
SA
Lynch
C Daniel
CD
Smith
David D
DD
Thiel
D000328:Adult; D000368:Aged; D050110:Bariatric Surgery; D002118:Calcium / Q000652:urine; D019343:Citric Acid / Q000652:urine; D003191:Comprehensive Health Care; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010070:Oxalates / Q000652:urine; D011446:Prospective Studies
D010070:Oxalates; D019343:Citric Acid; D003404:Creatinine; D002118:Calcium