Stage of fibrosis is not a predictive determinant of weight loss in patients undergoing bariatric surgery

Background Obesity and Non-alcoholic fatty liver disease (NAFLD) are an increasing health care burden, worldwide. Weight loss is currently the best option to alleviate NAFLD and is efficiently achieved by bariatric surgery. Presence of NAFLD seems to be predictive for postoperative weight loss. To date, only few predictive factors for post-bariatric weight loss (age, diabetes, psychiatric disorders) are established. Objectives Since liver fibrosis is the pathogenic driver for the progression of liver disease, we investigated its role in predicting postoperative weight loss. This study focuses on the correlation between fibrosis stage and weight loss. Setting University and university-affiliated cooperation, Germany. Methods We used a prospective, single-center cohort study including 164 patients who underwent bariatric surgery with simultaneous liver biopsies. Liver fibrosis was determined histologically according to Kleiner score and non-invasively by APRI and FIB-4 score. Percentage of total body weight loss was calculated at one-year follow up visit. Results. 32 patients were found without fibrosis, whereas 91 patients showed mild fibrosis (F1), 37 significant fibrosis (F2), and only four patients presented advanced fibrosis (F3) at the time of bariatric surgery. Weight loss was similar across different degrees of fibrosis stage. Accordingly, linear regression analysis did not identify predictors of weight loss among fibrosis scores. In multivariable analysis, age and presence of diabetes showed the strongest predictive value. Conclusions Baseline presence of fibrosis was not associated with postoperative weight loss, while age and diabetes were independent predictors of weight loss. Bariatric surgery should be applied independently of the fibrosis stage.