Abstract
Objectives
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.
Methods
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.
Results
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.
Conclusion
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.
Trial registration number: Australian Clinical Trials Registry (ACTRN12610000049077).
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Abbreviations
- NAFLD:
-
Nonalcoholic fatty liver disease
- ALT:
-
Alanine aminotransferase
- GGT:
-
Gamma glutamyltransferase
- TBWL:
-
Total body weight loss
- NASH:
-
Nonalcoholic steatohepatitis
- EWL:
-
Excess weight loss
- BMI:
-
Body mass index
- HDL:
-
High-density lipoprotein
- LDL:
-
Low-density lipoprotein
- hsCRP:
-
Highly sensitive C-reactive protein
- NAS:
-
NAFLD activity score
- GEE:
-
Generalized estimating equation
- SBP:
-
Systolic blood pressure
- DBP:
-
Diastolic blood pressure
- AUROC:
-
Area under the receiver operator characteristic curve
- LAGB:
-
Laparoscopic adjustable gastric band
- HCV:
-
Hepatitis C virus
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Acknowledgements
We acknowledge the kind support of the Royal Australasian College of Surgeons and the National Health and Medical Research Council in supporting Dr. Ooi and Dr. Doyle in their higher degrees and in completing this research.
We thank Ms. Cheryl Laurie and Ms. Julie Playfair, Mr. Stuart Skinner, and Mr. Andrew Smith for their contribution and enthusiasm in recruitment and follow-up of participants, and collection of samples.
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Conflict of Interest
The Centre for Obesity Research and Education has received funding for research purposes from Allergan, Inc., the manufacturer of the LAP-BAND.
Prof Cowley reports grants and personal fees from Novo Nordisk, and personal fees and other from Orexigen Therapeutics, outside the submitted work.
Prof Brown reports financial support for a bariatric surgery registry from the Commonwealth of Australia, Apollo Endosurgery, Covidien, Johnson and Johnson, Gore, and Applied Medical.
Dr. Ooi and Dr. Doyle report scholarships from the National Health and Medical Research Council and the Royal Australasian College of Surgeons.
PRB, JMW, PSB, KS, SKR, WK, AE, and PEO have no other disclosures or conflicts of interest.
Ethical Approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
This article does not contain any studies with animals performed by any of the authors.
Informed Consent
Informed consent was obtained from all individual participants included in the study.
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Ooi, G.J., Burton, P.R., Doyle, L. et al. Effects of Bariatric Surgery on Liver Function Tests in Patients with Nonalcoholic Fatty Liver Disease. OBES SURG 27, 1533–1542 (2017). https://doi.org/10.1007/s11695-016-2482-8
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DOI: https://doi.org/10.1007/s11695-016-2482-8