Long-term effect of bariatric surgery on resolution of nonalcoholic steatohepatitis (NASH): An external validation and application of a clinical NASH score

Background Nonalcoholic steatohepatitis (NASH) is an important etiology of end-stage liver disease. Long-term effect of bariatric surgery in improvement of NASH is not clear. Objectives To validate a scoring system for predicting NASH in morbidly obese patients and using it to evaluate the long-term effect of bariatric surgery on NASH. Setting Tertiary referral hospital, Taiwan. Methods A new 5-point clinical NASH (C-NASH) score incorporating body mass index, alanine aminotransferase, and triglyceride was validated in a group of 307 bariatric patients (mean age 30.2 years, incorporating body mass index 45.0 kg/m2) with concurrent liver biopsy from 2003 to 2008. Remission of NASH in 5741 obese patients undergoing bariatric/metabolic surgery with long-term follow-up was then evaluated using the C-NASH score. Results Among 307 patients with liver biopsy, the prevalence of NASH was 44.0%. At baseline, the NASH group had significantly worse fasting glucose levels, triglycerides, uric acid, aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transferase, and glycated hemoglobin. The diagnostic sensitivity of C-NASH score was 84.4%, and the accuracy was 68.4%. Among 5741 bariatric patients, the prevalence of high risk for NASH evaluated by C-NASH score was 40.9%. Postoperative follow-up showed good weight loss and almost complete remission of high risk for NASH up to 10 years. Patients with gastric banding had less weight loss, higher mean level of C-NASH score, and a higher incidence of high risk for NASH compared with other procedures at follow-up. Conclusion This study demonstrated that improvement in C-NASH score suggesting remission of NASH is durable up to 10 years in all kinds of bariatric procedures.