CHICAGO – Grade 2 or 3 hepatic fibrosis in the setting of nonalcoholic fatty liver disease resolved or improved in 56% of affected patients following their bariatric surgery for severe obesity, according to a large blinded, paired-biopsy study.
Bariatric surgery in patients with nonalcoholic fatty liver disease (NAFLD) also achieved a high rate of resolution of steatosis and steatohepatitis, but it was the improvement in advanced fibrosis, including stage 3 or bridging fibrosis, that was particularly impressive. Traditionally, liver fibrosis was thought to be an irreversible finding, Dr. Andrew A. Taitano observed at the annual Digestive Disease Week.
Dr. Andrew A. Taitano
"Our data provide strong evidence that bariatric surgery improves liver histology in NAFLD," he said. "We conclude that bariatric surgery should be considered one of the treatments for NAFLD in patients with severe obesity."
Dr. Taitano presented a retrospective, single-center study of 160 patients with NAFLD at the time they underwent bariatric surgery for weight loss, all of whom had follow-up liver biopsies when they underwent abdominal operations for any reason an average of 31 months later. Their mean body-mass index was 52 kg/m2 at bariatric surgery, with a 62% excess body weight loss at the time of their subsequent abdominal surgery.
At bariatric surgery, 65% of patients had hepatic fibrosis. At follow-up, two blinded pathologists reported that only 36% of patients had liver fibrosis. Fibrosis was resolved or improved by at least one grade in 56% of patients, worse in 16%, and unchanged in the rest, reported Dr. Taitano, a bariatric surgery fellow at the University of South Florida, Tampa.
Of 56 patients without baseline liver fibrosis, only 12 had developed fibrosis at follow-up.
Steatosis was present in 77% of patients at bariatric surgery and in 21% at follow-up. Steatosis was resolved in 86% of patients at follow-up, the same in 8%, and worse in 6%, he said.
Steatohepatitis was found on liver biopsies at bariatric surgery in 26% of patients but was present in only 3% at follow-up. This form of histopathology was resolved or improved at follow-up in 93% of affected patients; fibrosis was worse in none.
NAFLD is the most common liver disorder in Western countries. The rate has doubled in the last 20 years. Risk factors include type 2 diabetes, central obesity, and dyslipidemia – all features of the metabolic syndrome. NAFLD is a progressive disease. Previous studies indicate that up to half of patients with NAFLD develop fibrosis within 13 years, and it’s estimated that one in five patients with NAFLD with steatohepatitis will develop cirrhosis within 20 years.
Dr. Guilherme M. Campos
Discussant Dr. Guilherme M. Campos, a surgeon at the University of Wisconsin, Madison, commented, "It’s important to underscore that the magnitude of histologic improvements observed here is far greater than seen with maximum nonoperative therapy."
Asked if the study data pointed to any particular type of bypass surgery or any patient characteristics that correlate with change in NAFLD histopathology, Dr. Taitano replied that gastric bypass was the predominant operation. Although the limited patient numbers didn’t permit meaningful comparisons, he said, "as an overall recommendation, I would advise a weight-loss procedure that has a metabolic effect, such as gastric bypass, because I think both the amount of weight loss and the operation’s metabolic effect are improving this disease."
He reported having no financial conflicts regarding this study, which was conducted using institutional funds.