title: Acute kidney injury following bariatric surgery.
abstract: BACKGROUND
  Postoperative acute kidney injury (AKI) following bariatric surgery has not been well studied. The aim of this study is to identify factors associated with risk of AKI.
  
  
  METHODS
  The medical records of adult patients who underwent bariatric surgery between March 1, 2005 and March 31, 2011 at the Mayo Clinic were reviewed to identify patients who experienced AKI, defined as postoperative increase in serum creatinine (sCr) by 0.3 mg/dL within 72 h. For each AKI case, two controls were matched for surgical approach (laparotomy vs. laparoscopic). A chart review was conducted and conditional logistic regression analyses were performed to identify risk factors for AKI.
  
  
  RESULTS
  There were 1,227 patients who underwent bariatric surgery, and of these, 71 developed AKI (5.8 %). The median sCr increase was 0.4 (interquartile range 0.3-0.6) mg/dL. Independent patient factors associated with increased risk included higher body mass index [odds ratio (OR) 1.24, 95 % CI 1.06-1.46 per 5 unit increase, P = 0.01] and medically treated diabetes mellitus (OR 2.77, 1.36-5.65, P = 0.01). Patients experiencing AKI had higher rates of blood transfusions (P < 0.01), postsurgical complications (P < 0.01), and longer hospital stays (P < 0.01). Another 30 patients developed kidney injury after 72 postoperative hours, usually in the setting of dehydration.
  
  
  CONCLUSIONS
  Kidney injury following bariatric surgery is not uncommon and is associated with higher body mass index and diabetes. Further, there should be a high risk of suspicion for kidney injury in postoperative patients developing volume depletion.
authors.affiliation: Department of Anesthesiology, Mayo Clinic College of Medicine, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA. weingarten.toby@mayo.edu
authors.forename: Toby N
authors.initials: TN
authors.lastname: Weingarten
authors.forename: Carmelina
authors.initials: C
authors.lastname: Gurrieri
authors.forename: Joan M
authors.initials: JM
authors.lastname: McCaffrey
authors.forename: Starla J
authors.initials: SJ
authors.lastname: Ricter
authors.forename: Mandy L
authors.initials: ML
authors.lastname: Hilgeman
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Schroeder
authors.forename: Michael L
authors.initials: ML
authors.lastname: Kendrick
authors.forename: Eddie L
authors.initials: EL
authors.lastname: Greene
authors.forename: Juraj
authors.initials: J
authors.lastname: Sprung
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology* / Q000628:therapy; D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D001803:Blood Transfusion; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D003681:Dehydration / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000401:mortality / Q000601:surgery*; D011183:Postoperative Complications; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D003404:Creatinine