LAUSR

OBJECTIVE To compare histological outcomes in patients with fibrotic nonalcoholic steatohepatitis (NASH) and obesity after metabolic surgery versus nonsurgical care. BACKGROUND There are no published data comparing the effects of metabolic surgery versus nonsurgical care on histological progression of NASH. METHODS Repeat liver biopsies were performed in patients with BMI >30 kg/m2 at a US health system whose baseline liver biopsy between 2004 and 2016 confirmed a histological diagnosis of NASH including presence of liver fibrosis, but without cirrhosis. Baseline characteristics of liver histology for patients who underwent simultaneous liver biopsy at the time of metabolic surgery were balanced with a nonsurgical control group using overlap weighting methods. The primary composite end point required both resolution of NASH and improvement of at least 1 fibrosis stage in the repeat liver biopsy. RESULTS 133 patients (42 metabolic surgery and 91 nonsurgical controls) had a repeat liver biopsy with a median interval of 2 years. Overlap weighting provided balance for baseline histological disease activity, fibrosis stage, and time interval between liver biopsies. In overlap-weighted patients, 50.1% in the surgical and 12.1% in the nonsurgical group met the primary end point (odds ratio 7.3 [95% CI, 2.8-19.2], P<0.001). NASH resolution and fibrosis improvement occurred in 68.5% and 64.1% of surgical patients, respectively. Surgical and nonsurgical patients who met the primary end point lost more weight than their counterparts who did not meet the primary end point (mean weight loss difference in the surgical group 12.2% [95% CI, 7.3%-17.2%] and in the nonsurgical group 11.6% [95% CI, 6.2%-16.9%]). CONCLUSIONS Among patients with fibrotic non-cirrhotic NASH, metabolic surgery resulted in simultaneous NASH resolution and fibrosis improvement in half of patients.