Liver pathology in morbidly obese patients undergoing Roux-en-U gastric bypass surgery

Background: Non-alcoholic fatty liver disease is common. However, little is known about liver disease in the morbidly obese. Methods: 75 subjects (78% female, mean BMI 57 [40-108]) who had intra-operative liver biopsies at the time of Roux-en-Y gastric bypass surgery were studied. Results: 84% of subjects had steatosis while only about 20% had moderate to severe inflammation and fibrosis. 8% had bridging fibrosis or cirrhosis. The presence of fibrosis correlated strongly with the presence of inflammation (p<0.001) and steatosis (p=0.0011), but weakly with ALT (p=0.02) and not with AST (p=0.12) or with BMI (p=0.34). Steatosis correlated with AST (p=0.04) and ALT (p=0.055), but not with BMI. Conclusion: Liver disease is not rare in the morbidly obese. The exact causes and mechanisms that lead from the very common isolated steatosis to inflammation and fibrosis remain unclear. Intra-operative liver biopsies during bariatric surgery may be helpful to screen for the presence of steatohepatitis and fibrosis.