Aims: To prospectively examine the effect of modern bariatric surgery on 24-hour urine parameters in a comprehensive care bariatric practice (CCBP).
Materials and 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.
Written by:
Hutchinson R, Parker AS, Arnold M, Bowers SP, Haley WE, Diehl N, Stone R, Lynch SA, Smith CD, Thiel DD. Are you the author?
Department of Urology, Department of Health Sciences Research, Department of General Surgery, Department of Nephrology, and Department of Nutrition Services, Mayo Clinic, Jacksonville, FL, USA.
Reference: Clin Nephrol. 2014 Feb 5. Epub ahead of print.
doi: 10.5414/CN108154
PubMed Abstract
PMID: 24495903
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