Bariatric Surgery Could Resolve Liver Disease in the Obese

A recent study has found an improvement in the histopathological features of nonalcoholic fatty liver disease (NAFLD) following bariatric (weight loss) surgery.

Researchers at the University of Texas Medical Branch (Galveston, USA) conducted a meta-analysis of 15 studies involving 766 patients with paired liver biopsies. Studies of jejuno-ileal bypass were excluded, as were those with fewer than 10 patients. The mean age of the participants at the time of weight loss surgery ranged from 35.6 to 49 years. The mean body mass index (BMI) at the time of surgery ranged from 43.9 to 56, and the mean BMI at follow-up liver biopsies ranged from 28.6 to 39. The percentage reduction in mean BMI values following surgery ranged from 19.11 to 41.76.

The results of the analysis showed that the pooled proportion of patients with improvement or resolution in steatosis (fat accumulation in the liver cells) was 91.6%, severe non-alcoholic steatohepatitis (NASH) resolution was 81.3%, fibrosis (which can progress to cirrhosis) resolution was 65.5%, and complete resolution of NASH was 69.5%. The researchers stressed that the confirmation of these results may require further multi-center, large scale, well designed trials, and that future studies also need to be conducted using uniform histopathological criteria for liver biopsy specimens. The study was published in the December 2008 issue of Clinical Gastroenterology and Hepatology

"Even today, the effect of weight loss after bariatric surgery on the liver, particularly NAFLD, remains unclear. There is a lack of well-defined trials exploring this relationship," said lead author Gagan Sood, M.D. "Our team assessed and quantified this effect and found encouraging news; a majority of patients experience complete resolution of NAFLD after bariatric surgery, and the risk of progression of inflammatory changes and fibrosis seems to be minimal."

NAFLD encompasses a range of conditions involving the liver that affect people who drink little or no alcohol, and ranges from hepatic steatosis to end-stage liver disease and hepatocellular carcinoma. The prevalence of NAFLD is estimated to be around 70% in obese individuals and 85-95% in patients with morbid obesity. The prevalence of NASH is as high as 18.5% in obese individuals and 33% in those who are morbidly obese. The pathophysiologic mechanisms of NAFLD have not been clearly elucidated yet, but obesity and insulin resistance are considered the main causative factors.

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University of Texas Medical Branch