Occult hepatitis B virus infection predicts non-alcoholic steatohepatitis in severely obese individuals from Italy

Background & Aims: Obesity is associated with non-alcoholic fatty liver (NAFL), which may progress towards non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Occult hepatitis B virus infection (OBI) may contribute to hepatic damage in patients with chronic liver disease of different aetiologies (eg HCV, alcohol). However, information on the prevalence and clinical impact of OBI in obese individuals is lacking. The aims of this study were to investigate NASH prevalence and risk factors in obese people who underwent bariatric surgery. Methods: Two-hundred and twenty-six subjects (160 females; mean age 42.9 years ±10.8 SD) without evidence of any further cause of liver disease consecutively underwent bariatric surgery in two Italian liver centers. During surgery, all patients underwent liver biopsy for histological evaluation and molecular studies. Liver DNA extracts were tested for PNPLA3, TM6SF2, MBOAT7, IRGM polymorphisms and for OBI. Univariate and multivariate analyses were used to identify predictors of NASH. Results: Histology showed NASH in 115 (50.9%) and NAFL in 111 cases (49.1%). Twenty-nine/226 (12.8%) cases had OBI, 24 (82.8%) of whom had NASH and 5 (17.2%) NAFL, whereas among the 197 OBI-negative cases, 91 (46.2%) had NASH and 106 (53.8%) NAFL (P =.0002). Multivariate analysis showed that older age (P =.03, OR 1.034), alanine aminotransferase values (P =.005, OR 1.023), insulin resistance/diabetes (P =.02, OR 2.257), TM6SF2 polymorphism (P =.04, OR 3.168) and OBI (P =.004, OR 5.503) were independent predictors of NASH. Conclusion: NASH is highly prevalent in obese individuals undergoing bariatric surgery. OBI is one of the strongest risk factors of NASH in these patients.