Bariatric surgery reduces problems associated with non-alcoholic fatty liver disease

By Bridgett Novak

NEW YORK (Reuters Health) - Bariatric surgery resolves liver inflammation and reverses early-stage liver fibrosis among some patients with non-alcoholic fatty liver disease (NAFLD), according to a new study.

The research was presented May 4 at Digestive Disease Week in Chicago.

Researchers at the University of South Florida in Tampa compared findings from liver biopsies from 152 patients (82% women) between 1998 and 2013. The first biopsies were conducted at the time of the bariatric procedures (the majority of which were gastric bypass) and the second were conducted an average of 29 months later. Mean pre-op body mass index (BMI) was 52 kg/m2; by the time of the second biopsy, mean amount of excess weight loss was 62%.

The findings on the initial biopsies were steatosis (78%), lobular inflammation (42%), chronic portal inflammation (68%), steatohepatitis (33%), Grade 2 fibrosis (34%), Grade 3 fibrosis (7%), and cirrhosis (2%).

On the post-op biopsies, steatosis had been resolved in 70% of patients. Lobular inflammation was resolved in 74%; chronic portal inflammation, in 32%; and steatohepatitis, in 88%.

Dr. Michel Murr, senior author and director of the Bariatric Center at Tampa General Hospital in Florida, told Reuters Health via email, "Even more significantly, we found that Grade 2 fibrosis resolved in 62% of the patients, and did not worsen in another 14%. The traditional teaching has been that liver fibrosis is 'progressive and irreversible.' We have lots of data from animal models regarding inflammation and steatosis, but the resolution of fibrosis was completely unanticipated."

Of the 10 patients with bridging or Grade 3 fibrosis, one resolved and seven improved. One of the three patients with cirrhosis also showed improvement. Dr. Murr noted that the fibrosis reversals applied only to early- and not late-stage liver disease. But he added, "At least 20% of patients with early stage NAFLD may progress to liver failure within ten years."

"Our findings thus suggest that providers should consider bariatric surgery as the treatment of choice for nonalcoholic fatty liver disease in severely obese patients (those with a BMI above 35 and obesity-related co-morbidities or a BMI above 40)," Dr. Murr said.

Dr. Stavra Xanthakos, co-director of the Steatohepatitis Center at Cincinnati Children's Hospital Medical Center in Ohio, told Reuters Health by email, "This data is exciting and adds to the existing literature that supports a very beneficial effect of weight loss surgery (WLS) on NAFLD histology."

She would like to see a longer, controlled trial comparing surgical interventions with lifestyle changes, though.

"A recent intensive lifestyle treatment program for obese adults showed an overall 67% resolution of steatohepatitis after one year (Promrat et al. Hepatology 2010;51:121). However in that study, the mean BMI was lower (34 kg/m2) than in this study and severely obese adults are likely to have more difficulty achieving significant or sustained weight loss with lifestyle interventions alone," Dr. Xanthakos noted.

About 30% of the U.S. population has NAFLD and more than half of patients are severely obese. NAFLD is projected to be the most common cause of liver disease in Western countries by 2020.

"The rapid rise of obesity in children is accompanied by an epidemic of NAFLD," Dr. Murr said. "Because the liver plays a central role in insulin sensitivity and diabetes, treating NAFLD will become the centerpiece in evolving concepts to treat obesity and its associated comorbidities."