Prospective evaluation of 24-hour urine profiles following bariatric surgery in a modern comprehensive care bariatric clinic

Ryan Hutchinson, Alexander S. Parker, Michelle Arnold, Steven P. Bowers, William E. Haley, Nancy Diehl, Ronald Stone, Scott A. Lynch, C. Daniel Smith, David D. Thiel

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


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%) had 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.

Original languageEnglish (US)
Pages (from-to)331-337
Number of pages7
JournalClinical Nephrology
Issue number5
StatePublished - 2014


  • Bariatric surgery
  • Nephrolithiasis
  • Nutrition
  • Roux-en-Y
  • Urinalysis

ASJC Scopus subject areas

  • Nephrology


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