Persistence of severe liver fibrosis despite substantial weight loss with bariatric surgery

BACKGROUND AND AIMS: It remains unclear to what extent and which components of advanced liver disease improve after bariatric surgery. We herein describe the histological outcome in patients with advanced NASH and its relationship with weight loss and metabolic improvement. APPROACH AND RESULTS: One hundred ninety-six patients with advanced NASH underwent bariatric surgery, 66 of whom agreed to a follow-up liver biopsy at 6 ± 3 years (36 with advanced fibrosis [AF] and 30 with high activity [HA] grade without AF). Liver biopsies LBs were centrally read and histological response was defined as the disappearance of AF or HA. Bariatric surgery induced major histological improvement: 29% of patients had normal histology at follow-up biopsy; 74% had NASH resolution without fibrosis progression; and 70% had ≥1 stage fibrosis regression. However, AF persisted in 47% of patients despite NASH resolution and some degree of fibrosis reversal, only evidenced by the EPoS seven-tier staging classification. These patients had lower weight loss and reduced hypertension or diabetes remission rates. Older age and sleeve gastrectomy were the only independent predictors for persistent AF after adjustment for duration of follow-up. All HA patients had major histological improvement: 50% normal histology, 80% NASH resolution, and 86% a ≥1 grade steatosis reduction. Patients with normal liver at follow-up had the largest weight loss and metabolic improvement. Independent predictors of normal liver were amount of weight loss, high histological activity, and the absence of AF before surgery. CONCLUSIONS: Although bariatric surgery successfully reverses active steatohepatitis, AF can persist for many years and is associated with lesser weight loss and metabolic improvement. Weight loss alone may not be sufficient to reverse AF.