title: Bariatric surgery reduces urinary albumin excretion in diabetic nephropathy: a systematic review and meta-analysis.
abstract: BACKGROUND
  Bariatric surgery is found to prevent type 2 diabetes, improve glycemic control, and decrease long-term incidence of microvascular and macrovascular complications in obese persons. However, its effect on urinary albumin excretion (UAE) in patients with diabetic nephropathy (DN) is still unknown. This is a systematic review and meta-analysis of observational studies on bariatric surgery and change in UAE in patients with diabetes.
  
  
  OBJECTIVE
  To explore whether there is improvement in UAE after bariatric surgery.
  
  
  METHODS
  We comprehensively searched the databases of MEDLINE, Embase, and Cochrane. The inclusion criteria were published studies evaluating effects of bariatric surgery in patients with DN at baseline. The primary outcome was the pre- and postbariatric surgery UAE as characterized by urinary albumin-to-creatinine ratio and albuminuria. A meta-analysis comparing pre- and postsurgery UAE was performed.
  
  
  RESULTS
  From 65 full-text articles, 15 observational studies met our inclusion criteria, and 11 studies were included in the meta-analysis based on the random effects model. There was a significant reduction in urinary albumin-to-creatinine ratio after bariatric surgery with a mean difference of -6.60 mg/g of creatinine (95% CI -9.19 to -4.02; P<.001). There was also a reduction in albuminuria with a mean difference of -55.76 mg/24 hours (95% CI -92.11 to -19.41; P<.001) after bariatric surgery.
  
  
  CONCLUSIONS
  Bariatric surgery significantly decreases urinary albumin excretion in DN. However, studies comparing bariatric surgery and conventional or intensive care of diabetes on UAE outcome should be done.
authors.affiliation: Department of Internal Medicine, Bassett Medical Center and Columbia University College of Physicians and Surgeons, Cooperstown, New York; Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sikarin
authors.initials: S
authors.lastname: Upala
authors.affiliation: Department of Internal Medicine, Bassett Medical Center and Columbia University College of Physicians and Surgeons, Cooperstown, New York.
authors.forename: Karn
authors.initials: K
authors.lastname: Wijarnpreecha
authors.affiliation: Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Soontharee
authors.initials: S
authors.lastname: Congrete
authors.affiliation: Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Pattara
authors.initials: P
authors.lastname: Rattanawong
authors.affiliation: Department of Internal Medicine, Bassett Medical Center and Columbia University College of Physicians and Surgeons, Cooperstown, New York; Department of Preventive and Social Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Electronic address: anawin.sanguankeo@bassett.org.
authors.forename: Anawin
authors.initials: A
authors.lastname: Sanguankeo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000517:prevention & control*; D050110:Bariatric Surgery; D003922:Diabetes Mellitus, Type 1 / Q000517:prevention & control*; D003924:Diabetes Mellitus, Type 2 / Q000517:prevention & control*; D003928:Diabetic Nephropathies / Q000517:prevention & control*; D004812:Epidemiologic Methods; D006801:Humans; D008875:Middle Aged; D011182:Postoperative Care; D011300:Preoperative Care; D016896:Treatment Outcome; D055815:Young Adult
keywords: Bariatric surgery; Diabetic nephropathy; Microvascular complication; Proteinuria; Urinary albumin excretion