Andisheh Norouzian Ostad - Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Mohsen Nematy - Biochemistry and Nutrition Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
Ali Jangjoo
Reza Rezvani - Biochemistry and Nutrition Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

Introduction: The overall effect of weight loss and RYGB on liver fibrosis remains unclear, especially among Middle Eastern populations. This study aimed to evaluate the influence of weight change on the liver fibrosis after 2-years of RYGB.Methods: We prospectively evaluated 44 morbidly obese patients aged 44.7 ± 10 years who underwent RYGB. NAFLD was confirmed in all patients with the biopsy at the time of surgery. Liver stiffness was measured by Two-dimensional shear wave Elastography (2D-SWE) before surgery and after 2 years, and the correlations between hepatic fibrosis and weight changes following gastric bypass surgery were analyzed. Anthropometric data was also assessed at baseline and at the time of the second 2D-SWE.Results: 37 of the participants were women and seven were men. Average weight loss after 2 years was 42 ± 1.62 kg. Mean weight at baseline and after 24 months were 120.5 ± 20 kg and 78.5±13.9 kg respectively (P<0.001). After 2 years, two of the 43 patients had progressed liver fibrosis stage (4.7%), 18 recovered (41.9%) and 23 remained unchanged (53.5%). There was a significant improvement in fibrosis stage (P < 0.05). The persistence of fibrosis (F > 1) was present in three patients at the second 2D-SWE (6.9%) and two new cases of fibrosis were determined (4.6%). Patients with progressive fibrosis had more reduction in BMI kg/m2 compared to recovered patients (24.8 vs 15.8). Patients with progressive fibrosis were younger than improved patients (43.5 ± 10.4 vs 54) which was not statistically significant.Conclusions: Through this study, we found that RYGB provides significant weight loss and resolution of liver fibrosis in most morbidly obese patients. However, some patients develop worsened aspect of NAFLD. Further studies with higher sample size and longer time are needed.

Gastric bypass surgery, Weight, Non-alcoholic fatty liver disease, Morbid Obesity, Elasticity Imaging Techniques, Liver Diseases/diagnostic imaging