title: A Critical Analysis of Perioperative Outcomes in Morbidly Obese Patients Following Renal Mass Surgery.
abstract: OBJECTIVE
  To evaluate if body mass index (BMI) ≥ 40 is associated with risk of postoperative complications, receipt of perioperative blood transfusion (PBT), length of hospital stay (LOS), perioperative death, or hospital readmission rate following renal mass surgery.
  
  
  METHODS
  After Institutional Review Board approval, comprehensive information was collected for patients treated with surgery for renal mass from 2000 to 2015 at one institution. Univariable and multivariable analyses were used to evaluate the association of BMI ≥ 40 among other putative risk factors for perioperative outcomes.
  
  
  RESULTS
  A total of 1048 patients were treated surgically, including 115 (11%) with BMI > 40. Minimally invasive and open surgical approaches were used for 480 (45.8%) and 568 (54.2%) patients, respectively. Morbid obesity was not associated with risk of major complications, overall complications, receipt of PBT, LOS, hospital readmission rate, or perioperative death. Charlson comorbidity index was the only independent predictor of major complications following renal mass surgery, P = .0006, per point odds ratio 1.2 (95%C.I. 1.08-1.32). Surgical site infections (SSIs) were more common in patients with BMI ≥ 40 vs BMI < 40 (10.5% vs 4.8%, P = .01). Following multivariable analysis, BMI ≥ 40 was the only independent predictor of SSIs, odds ratio 2.6, 95% confidence interval 1.32-5.13; P = .006.
  
  
  CONCLUSIONS
  Morbid obesity (BMI ≥ 40) is an independent predictor of developing SSIs following renal mass surgery. Morbid obesity is not predictive of risk for major complications, receipt of PBT, hospital readmission, perioperative death, or LOS.
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Grimes
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Blute
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Tyler A
authors.initials: TA
authors.lastname: Wittmann
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mann
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Kristin
authors.initials: K
authors.lastname: Zorn
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Tracy M
authors.initials: TM
authors.lastname: Downs
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Shi
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: David F
authors.initials: DF
authors.lastname: Jarrard
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Best
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Richards
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Nakada
authors.affiliation: Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, WI. Electronic address: abel@urology.wisc.edu.
authors.forename: E Jason
authors.initials: EJ
authors.lastname: Abel
mesh_terms: D000368:Aged; D001803:Blood Transfusion / Q000706:statistics & numerical data; D015992:Body Mass Index; D006801:Humans; D007680:Kidney Neoplasms / Q000150:complications* / Q000601:surgery*; D007902:Length of Stay / Q000706:statistics & numerical data; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications*; D010359:Patient Readmission / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D018570:Risk Assessment; D016896:Treatment Outcome