Impacts of bariatric surgery on adverse liver outcomes: a systematic review and meta-analysis

Bariatric surgery has been reported to improve degeneration, inflammation, and fibrosis in nonalcoholic fatty liver disease, but the effects of bariatric surgery on the associated clinical outcomes is not known.This work aimed to assess the impacts of bariatric surgery on adverse liver outcomes in people with obesity.An electronic search was performed on EMBASE, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL).The primary outcome was the incidence of adverse liver outcomes following bariatric surgery. Liver cancer, cirrhosis, liver transplantation, liver failure, and liver-related mortality were defined as adverse hepatic outcomes.We analyzed data from 18 studies comprising 16,800,287 post bariatric surgical patients and 10,595,752 control patients. We found that bariatric surgery reduced the risk of adverse liver outcomes in people with obesity (hazard ratio [HR] = .33, 95% confidence interval [CI] = .31-.34; I2 = 98.1%). The subgroup analysis showed that bariatric surgery reduced the risk of nonalcoholic cirrhosis (HR = .07, 95% CI = .06-.08; I2 = 99.3%) and liver cancer (HR = .37, 95% CI = .35-.39; I2 = 97.8%), although bariatric surgery may also increase the risk of postoperative alcoholic cirrhosis (HR = 1.32, 95% CI = 1.35-1.59).This systematic review and meta-analysis revealed that bariatric surgery lowered the incidence of adverse hepatic outcomes. However, bariatric surgery may also increase the risk of alcoholic cirrhosis after surgery. Future randomized controlled trials are required to further investigate the effects of bariatric surgery on liver of people with obesity.