title: Estimated GFR Before and After Bariatric Surgery in CKD.
abstract: BACKGROUND
  Several reviews have recently detailed the beneficial effects of weight loss surgery for kidney function. However, these studies have a number of limitations, including small sample size, few done in chronic kidney disease (CKD) stages 3 and 4, and many not including the main bariatric surgery procedures used in the United States today.
  
  
  METHODS
  This was an observational retrospective cohort study comparing propensity score-matched bariatric surgery patients and nonsurgery control patients who were referred for, but did not have, surgery. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy were also compared using propensity matching.
  
  
  METHODS
  Patients (714 surgery patients; 714 controls) were from a large integrated health care system, a mean of 58±8 (SD) years old, and mostly women (77%) and non-Hispanic whites (56%) and had diabetes mellitus (66%) and/or hypertension (91%).
  
  
  METHODS
  Predictors at the time of surgery or referral to surgery were age, sex, race/ethnicity, weight, and presence of diabetes and/or hypertension.
  
  
  RESULTS
  The primary outcome for this study was change in estimated glomerular filtration rate (eGFR) from serum creatinine level over a median 3-year follow-up period.
  
  
  METHODS
  Serum creatinine was used to calculate eGFR using the CKD-EPI (CKD Epidemiology Collaboration) creatinine equation.
  
  
  RESULTS
  Surgery patients had 9.84 (95% CI, 8.05-11.62) mL/min/1.73m2greater eGFRs than controls at a median 3 years' follow-up and RYGB patients had 6.60 (95% CI, 3.42-9.78) mL/min/1.73m2greater eGFRs than sleeve gastrectomy patients during the same period.
  
  
  CONCLUSIONS
  This study is limited by its nonrandomized observational study design, estimation of GFR, and large changes in muscle mass, which may affect serum creatinine level independent of changes in kidney function.
  
  
  CONCLUSIONS
  Bariatric surgery, especially the RYGB procedure, results in significant improvements for up to 3 years in eGFRs for patients with CKD stages 3 and 4.
authors.affiliation: Department of Nephrology, Fontana Medical Center, Kaiser Permanente Southern California, Fontana. Electronic address: talha.h.imam@kp.org.
authors.forename: Talha H
authors.initials: TH
authors.lastname: Imam
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Heidi
authors.initials: H
authors.lastname: Fischer
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Bocheng
authors.initials: B
authors.lastname: Jing
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Raoul
authors.initials: R
authors.lastname: Burchette
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Shayna
authors.initials: S
authors.lastname: Henry
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Stephen F
authors.initials: SF
authors.lastname: DeRose
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Coleman
mesh_terms: D050110:Bariatric Surgery; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000503:physiopathology* / Q000601:surgery*; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000503:physiopathology*; D012189:Retrospective Studies
keywords: CKD progression; CKD stages 3-4; Estimated glomerular filtration rate (eGFR); Roux-en-Y gastric bypass (RYGB); bariatric surgery; chronic kidney disease (CKD); eGFR trajectory; obesity; renal function; sleeve gastrectomy (SG)