Impacts Of Bariatric Surgery On Adverse Liver Outcomes: A Systematic Review And Meta-analysis

Background: With the global epidemic of obesity,it has led to a rise in the number of people with non-alcoholic fatty liver disease(NAFLD).Nonalcoholic fatty liver disease is the leading cause of chronic liver disease in developed countries and a major contributor to liver-related mortality and morbidity.Yet effective treatments for non-alcoholic fatty liver disease are very limited.The search for effective treatment options therefore remains a priority in this field.Bariatric surgery has been reported to improve degeneration,inflammation,and fibrosis in non-alcoholic fatty liver disease(NAFLD),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.Setting: An electronic search was performed on EMBASE,Pub Med,and Cochrane Central Register of Controlled Trials(CENTRAL).Methods: The primary outcome was the incidence of adverse liver outcomes following bariatric surgery.An additional hand search was conducted for the integrity of the study.After rigorous exclusion and inclusion criteria,and quality assessment of the included literature,a pooled analysis was then performed using stats software.Liver cancer,cirrhosis,liver transplantation,liver failure,and liver-related mortality were defined as adverse hepatic outcomes.Results: We analyzed data from 18 studies comprising 1,197,148 post bariatric surgical patients and 1,800,380 control patients.We found that bariatric surgery reduced the risk of adverse liver outcomes in people with obesity(hazard ratio(HR)= 0.33,95% confidence interval(CI)=0.31-0.34;I2 = 98.1%).The subgroup analysis showed that bariatric surgery reduced the risk of non-alcoholic cirrhosis(HR = 0.07,95% CI = 0.06-0.08;I2 = 99.3%)and liver cancer(HR = 0.37,95% CI = 0.35-0.39;I2 = 97.8%),although bariatric surgery may also increase the risk of postoperative alcoholic cirrhosis(HR = 1.32,95% CI =1.35-1.59).Conclusions: This systematic review and meta-analysis revealed that bariatric surgery lowered the incidence of adverse hepatic outcomes.Bariatric surgery can slow down the progression of non-alcoholic fatty liver disease and reduce the risk of non-alcoholic cirrhosis and liver cancer.However,bariatric surgery may also increase the risk of alcoholic cirrhosis after surgery.For patients undergoing bariatric surgery,post-operative alcohol monitoring is necessary to reduce the risk of alcoholic cirrhosis.Future randomized controlled trials(RCT)are required to further investigate the effects of bariatric surgery on liver of people with obesity.