Distinct Histologic Spectrum of Nonalcoholic Fatty Liver Disease in Morbidly Obese Bariatric Surgery Cohort of African Americans Presidential Poster: 2167

Introduction: Morbid obesity (BMI ≥40 kg/m2) is associated with nonalcoholic fatty liver disease (NAFLD). The spectrum of NAFLD includes fatty liver (NAFL) or the more aggressive form steatohepatitis (NASH). An important determinant of liver disease severity is stage of fibrosis. We hypothesized that morbidly obese subjects have less aggressive and less severe liver disease on liver histology. Methods: All consecutive, intra-operative liver biopsies during the period 2005 to 2013, in bariatric surgery subjects were retrospectively studied. Pertinent clinical data were retrieved. Statistical analyses including correlation and regression analysis were performed as appropriate. Results: Of 242 subjects (female=205, male=37) the mean age was 44 ± 11 yrs and 165 (68.2%) were white (W) and 74 (30.6%) African Americans (AA). AAs had significant differences vs. W subjects for the following histologic features: AAs had 52% lower probability of developing steatosis (p=0.005 vs. W). Similarly, AAs had ˜60% less likelihood of significant lobular inflammation (p=0.01 vs. W). Also, probability of cytologic ballooning was lower in AAs vs. W (p=0.07). As a result, NAFLD Activity Score (NAS) was 47% more likely to be lower in AAs (p=0.007 vs. W). Further, AAs had ˜60% lower risk for advanced fibrosis (stages 3 and 4) (p=0.01 vs. W). Interestingly, advanced fibrosis was seen in 5.5% subjects while 94.5% subjects had non-significant fibrosis. In fact, 68% subjects had no reported fibrosis on liver histology. Older age was associated with higher probability of advanced fibrosis (p=0.02 vs. W). Similarly, increasing body weight rendered higher likelihood of advanced fibrosis (p=0.0004 vs. W). Conclusion: Morbidly obese African Americans who underwent bariatric surgery had a distinct spectrum of liver histology. African Americans were protected against higher grades of steatosis, lobular inflammation and cell injury as evident by decreased cytologic ballooning. Moreover, AA race also offered protection against advanced fibrosis. The mechanisms underlying AA race related protective effects could partly be related to genetics and merit further investigations that hold potential for novel diagnostic, prognostic and therapeutic prospects.