Morbid obesity, nonalcoholic fatty liver disease, and weight loss surgery

This study examines the impact of biliopancreatic diversion, a malabsorptive variant of gastric bypass, on liver histology.

Liver samples were collected from 689 severely obese (BMI 47 +/- 9 kg m(2)) patients undergoing biliopancreatic diversion. Exclusion criteria included: history of hepatitis, exposure to hepatotoxic medications, prior weight loss surgery, and alcohol consumption greater than 100 grams per week. One group of 14 patients had cirrhosis in their initial biopsy. Eleven of those 14 patients underwent multiple biopsies to monitor their liver disease. A second group of 104 patients had re-operations and a second liver biopsy. A hepatopathologist conducted blind evaluations of all biopsy specimens looking for steatosis and fibrosis.

All patients lost weight and showed improvement in their metabolic syndrome. Of the 104 patients undergoing re-operation with a second liver biopsy, 28 showed a decrease in severe fibrosis, while 42 patients developed mild fibrosis. On average, this group lost 38 +/- 18 kg over 41 +/- 25 post-surgical months. A sub-group analysis revealed an association between increased fibrosis and post-operative low serum albumin, diarrhea, pre-operative alcohol consumption, and menopausal status. The eleven patients with cirrhosis in their initial biopsy showed a reduction in their fibrosis grade (mean fibrosis grade from 5 to 3) during nine years of follow-up care.

These findings indicate that significant weight loss after biliopancreatic diversion can improve liver histology in patients with advanced fibrosis.