title: Effects of Bariatric Surgery on Liver Function Tests in Patients with Nonalcoholic Fatty Liver Disease.
abstract: Nonalcoholic fatty liver disease (NAFLD) affects over 80% of obese patients and is fueled by the metabolic syndrome. Weight loss is strongly advocated as a central treatment for NAFLD and has been shown to induce histological improvement. We aimed to define the patterns of improvement in NAFLD with weight loss and determine target weight goals for NAFLD resolution.
  
  
  
  A prospective study of 84 morbidly obese patients with NAFLD undergoing bariatric surgery was conducted. Intraoperative liver biopsies were taken. Monthly follow-up, including blood tests and measurements, was performed. We monitored improvements in NAFLD by monthly alanine aminotransferase (ALT) and gamma glutamyltransferase (GGT) levels over 1 year.
  
  
  
  There was rapid improvement in ALT, particularly in the first 6 months following surgery, with statistically significant reduction in ALT at 2 months (35 vs 27 IU/L, p < 0.001). In multivariate analysis, there were significantly increased odds of ALT normalization after a %TBWL of 10-15% (odds ratio 2.49, p = 0.005). The odds of resolution increased with increasing weight loss. Triglyceride levels (odds ratio 0.59, p = 0.021) and baseline NAFLD activity score (odds ratio 0.28, p < 0.001) were also significantly related to ALT normalization. Improvements in ALT occurred prior to metabolic improvement and well before traditional ideal weight goals were reached.
  
  
  
  Improvements in NAFLD occurred rapidly after bariatric surgery and were closely related to weight loss and metabolic factors. A 10-15% reduction in body weight is an appropriate target to achieve substantial improvement in ALT levels.
  
  
  
  Australian Clinical Trials Registry (ACTRN12610000049077).
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia. geraldine.ooi@monash.edu.
authors.forename: Geraldine J
authors.initials: GJ
authors.lastname: Ooi
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia.|Department of Surgery, Alfred Hospital, Melbourne, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Burton
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Doyle
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia.|Walter and Eliza Hall Institute, Melbourne, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Wentworth
authors.affiliation: Melbourne Pathology, East Melbourne, Australia.|Department of Pathology, Melbourne University, Melbourne, Australia.
authors.forename: Prithi S
authors.initials: PS
authors.lastname: Bhathal
authors.affiliation: Melbourne Pathology, East Melbourne, Australia.
authors.forename: Ken
authors.initials: K
authors.lastname: Sikaris
authors.affiliation: MODI, Monash University, Clayton, Australia.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Cowley
authors.affiliation: Department of Gastroenterology, Alfred Hospital, Melbourne, Australia.
authors.forename: Stuart K
authors.initials: SK
authors.lastname: Roberts
authors.affiliation: Department of Gastroenterology, Alfred Hospital, Melbourne, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Kemp
authors.affiliation: Department of Epidemiology, Monash University, Clayton, Australia.
authors.forename: Arul
authors.initials: A
authors.lastname: Earnest
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia.
authors.forename: Paul E
authors.initials: PE
authors.lastname: O'Brien
authors.affiliation: Centre for Obesity Research and Education, Monash University, 99 Commercial Road, Melbourne, Australia.|Department of Surgery, Alfred Hospital, Melbourne, Australia.
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Brown
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001315:Australia; D050110:Bariatric Surgery; D005260:Female; D006801:Humans; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood / Q000150:complications* / Q000473:pathology; D009767:Obesity, Morbid / Q000097:blood / Q000150:complications / Q000473:pathology / Q000601:surgery*; D011446:Prospective Studies
chemical_list: D000410:Alanine Transaminase
keywords: Alanine transaminase; Bariatric surgery; Nonalcoholic fatty liver; Weight loss