Changes in renal function following Roux-en-Y gastric bypass: A prospective study

Jorge L Zelada Getty, Isam N. Hamdallah, Hazem N. Shamseddeen, Jennifer Wu, Roger K. Low, Jacqueline Craig, Mohamed R. Ali

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Background: Studies of the impact of Roux-en-Y gastric bypass (RYGB) on renal function have shown mixed results. We constructed this prospective repeated-measures controlled study to characterize this response and identify the best method of gauging renal function in this setting. Methods: Clinical data, serum creatinine (SC), and 24-h urine were collected 1 week before and 6 months following RYGB. Glomerular filtration rate (GFR) was calculated utilizing the Modification of Diet in Renal Disease formula. Creatinine clearance (CCL) was measured as a 24-h collection (24CCL) and calculated by the Cockcroft-Gault (CG) formula. Results: The study population of 37 patients (81% women) had a mean age of 47±11 years, had mean BMI of 47.6±6.3 kg/m 2, and achieved a mean % excess weight loss (EWL) of 60.9±17.1%. SC decreased from 0.83±0.21 mg/dl to 0.72±0.16 mg/dl (p<0.001) and mean GFR improved from 91.6±29.7 ml/min/1.73 m2 to 104.9±23.5 ml/min/1.73 m2 (p<0.01). Preoperatively, CG significantly overestimated CCL when compared with 24CCL (197.1±88.2 ml/min vs. 136.5±53.0 ml/min, p<0.001). In all patients, improvement in 24CCL correlated with EWL (r=0.32) and %EWL (r=0.16), and significantly correlated with decrease in BMI (r=0.51, p<0.005). In hypertensive patients, improvement in 24CCL significantly correlated with EWL (r=0.43, p<0.05), %EWL (r=0.40, p<0.05), and decrease in BMI (r=0.60, p<0.001) and was negatively correlated with age (r=-0.45, p<0.05). Conclusions: This study demonstrates that renal function improves following RYGB and is best identified by change in GFR. Improvement in 24CCL is correlated with the EWL success of the patient, especially hypertensive patients.

Original languageEnglish (US)
Pages (from-to)1055-1059
Number of pages5
JournalObesity Surgery
Issue number7
StatePublished - Jul 2012


  • Diabetes
  • Hypertension
  • Morbid obesity
  • Renal function
  • Roux-en-Y gastric bypass

ASJC Scopus subject areas

  • Surgery
  • Endocrinology, Diabetes and Metabolism
  • Nutrition and Dietetics


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