Original article
Pancreas, biliary tract, and liver
Effect of Weight Loss on Magnetic Resonance Imaging Estimation of Liver Fat and Volume in Patients With Nonalcoholic Steatohepatitis

https://doi.org/10.1016/j.cgh.2014.08.039Get rights and content

Background & Aims

Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method.

Methods

We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period.

Results

Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume.

Conclusions

A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points.

Section snippets

Study Design and Patient Population

This is a secondary analysis of a randomized controlled trial of 43 adult patients with biopsy-proven NASH. The primary outcome was change in MRI-estimated liver PDFF and MRI-estimated liver volume between the start (week 0) and completion (week 24) of the study. All patients were diagnosed with NASH on the basis of liver biopsy as well as exclusion of other causes of liver disease.34

As part of the original study, all patients were randomized to receive either colesevelam, a bile acid

Demographic and Biochemical Data of Patients

Forty-three patients with biopsy-confirmed NASH were included in this secondary analysis of a previously published randomized controlled trail. Between the start of the study (week 0) and the completion (week 24), 10 patients had at least 5% decrease in BMI, whereas 33 patients either gained weight or had less than 5% reduction in BMI. Overall, patients who had 5% or greater decrease in BMI lost an average of 4.73 kg (± 1.87), whereas patients who either gained weight or had less than 5%

Discussion

In this secondary analysis of a randomized controlled trial that uses an advanced, validated MRI method that allows noninvasive fat quantification of the liver, we demonstrate that patients with biopsy-proven NASH with at least 5% reduction in BMI have a significant decrease in MRI-estimated liver PDFF from 18.3% ± 7.6% to 13.6% ± 13.6%, a relative decrease of 25.5%. This weight loss is also associated with a reduction in liver volume. We also found that weight loss leads to a decrease in

Strengths and Limitations

The major strengths of this study include the use of a well-characterized patient population with biopsy-proven NASH and the use of an MRI technique that has been validated as a sensitive measure of changes in liver steatosis in patients with NAFLD. This study is also unique in assessing changes in liver volume and pancreatic fat content with weight loss. In addition, histologic assessment was available at the start and completion of our study. Despite this, we do acknowledge limitations of

Conclusions

A reduction in BMI of at least 5% is associated with a significant decrease in MRI-estimated liver PDFF and volume in patients with biopsy-proven NASH. Although weight loss resulted in a decrease in histology-determined steatosis grade, no decrease in NAS or reduction in transaminases was noted. These data have implications in assessing effect size in NAFLD and obesity trials that use MRI-estimated liver fat and volume as end points.

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    Conflicts of interest The authors disclose no conflicts.

    Funding The study was conducted at the Clinical and Translational Research Institute, University of California at San Diego. R.L. is supported in part by the American Gastroenterological Association (AGA) Foundation–Sucampo–ASP Designated Research Award in Geriatric Gastroenterology and by a T. Franklin Williams Scholarship Award. Funding provided by Atlantic Philanthropies, Inc, the John A. Hartford Foundation, the Association of Specialty Professors, and the American Gastroenterological Association and grant K23-DK090303-02 and by the UCSD Digestive Diseases Research Development Center, US PHS grant #DK080506. This research was partially supported by the Clinical & Translational Research Institute (CTRI) at the University of California, San Diego. The CTRI is funded from awards issued by the National Center for Advanced Translational Sciences, UL1RR031980. Dr Seki was supported by R01DK085252, R01AA02017204, and P42ES010337. Dr Sirlin was supported by R01DK088925.

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