title: The effect of underlying liver disease on short-term outcomes following bariatric surgery.
abstract: BACKGROUND
  Morbid obesity is strongly associated with nonalcoholic fatty liver disease. However, the effect of underlying liver disease on clinical outcomes following bariatric surgery has not been well studied. This study aims to determine the effect of underlying liver disease on short-term outcomes in bariatric patients using the model of end-stage liver disease (MELD) scoring system as a practical measure of hepatic dysfunction.
  
  
  METHODS
  A retrospective cohort analysis was performed using data from the American College of Surgeons' National surgery quality improvement program participant use files. The study population consisted of patients that underwent elective laparoscopic-stapled bariatric surgery for morbid obesity between 2005 and 2012. Patients were excluded if they had a bleeding disorder or renal failure requiring dialysis. The optimal MELD cut-off score to predict 30-day adverse events was determined and used to stratify patients into two groups. The primary outcome was 30-day adverse events, defined as a postoperative complication or reoperation. The secondary outcome was 30-day mortality. A multiple logistic regression was performed to adjust the odds ratio (OR) estimate for 30-day adverse events based on the MELD cut-off score.
  
  
  RESULTS
  38,875 patients were included in the study population. A MELD score of 7.9 was determined to be the optimal cut-off to predict 30-day adverse events based on the maximized linear combination of specificity and sensitivity. After adjusting for confounding, the OR estimates for 30-day adverse events and mortality using the cut-off score as the key predictor were 1.22 [95 % CI 1.06-1.41] and 2.33 [95 % CI 1.19-4.56], respectively.
  
  
  CONCLUSIONS
  Using this large national surgical registry, bariatric patients with MELD scores ≥7.9 had a significant but marginal risk of 30-day adverse events and mortality. This suggests that severity of liver disease may affect bariatric surgery outcomes and should be considered during preoperative evaluations.
authors.affiliation: Division of General Surgery, Department of Surgery, Toronto Western Hospital, University Health Network, University of Toronto, 399 Bathurst St, Toronto, ON, M5T 2S8, Canada, ahmadelnahas@gmail.com.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Elnahas
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Nguyen
authors.forename: Allan
authors.initials: A
authors.lastname: Okrainec
authors.forename: Fayez
authors.initials: F
authors.lastname: Quereshy
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Jackson
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000379:methods* / Q000401:mortality; D015331:Cohort Studies; D017558:Elective Surgical Procedures / Q000379:methods; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008107:Liver Diseases / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009767:Obesity, Morbid / Q000601:surgery*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
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