This article has an accompanying continuing medical education activity, also eligible for MOC credit, on page e61. Learning Objective-Upon completion of this activity, successful learners will be able to demonstrate an increase in, or affirmation of, their clinical knowledge of nonalcoholic fatty liver disease and identify the role of bariatric surgery in nonalcoholic fatty liver disease treatment. BACKGROUND & AIMS: Bariatric surgery has been reported to lead to complete resolution of nonalcoholic fatty liver disease (NAFLD) following the sustained weight loss induced in obese patients. We performed a systematic review and meta-analysis to evaluate the effects of bariatric surgery on NAFLD in obese patients. METHODS: We searched MEDLINE, EMBASE, CENTRAL, and Web of Science databases through May 2018 for studies that compared liver biopsy results before and after bariatric surgery in obese patients. Primary outcomes were biopsy-confirmed resolution of NAFLD and NAFLD activity score. Secondary outcomes were worsening of NAFLD after surgery and liver volume. The Grading of Recommendations, Assessment, Development, and Evidence approach was conducted to assess overall quality of evidence. RESULTS: We analyzed data from 32 cohort studies comprising 3093 biopsy specimens. Bariatric surgery resulted in a biopsy-confirmed resolution of steatosis in 66% of patients (95% CI, 56%-75%), inflammation in 50% (95% CI, 35%-64%), ballooning degeneration in 76% (95% CI, 64%-86%), and fibrosis in 40% (95% CI, 29%-51%). Patients' mean NAFLD activity score was reduced significantly after bariatric surgery (mean difference, 2.39; 95% CI, 1.58-3.20; P < .001). However, bariatric surgery resulted in new or worsening features of NAFLD, such as fibrosis, in 12% of patients (95% CI, 5%-20%). The overall Grading of Recommendations, Assessment, Development, and Evidence quality of evidence was very low. CONCLUSIONS: Through this systematic review and meta-analysis, we found that bariatric surgery leads to complete resolution of NAFLD in obese patients. However, some patients develop new or worsened features of NAFLD. Randomized controlled trials are needed to further examine the therapeutic benefits of bariatric surgery for patients with NAFLD.

Background: Bariatric surgery has been shown to significantly reduce cardiovascular risk factors. However, whether surgery can reduce major adverse cardiovascular events (MACE), especially in patients with established cardiovascular disease, remains poorly understood. The present study aims to determine the association between bariatric surgery and MACE among patients with cardiovascular disease and severe obesity. Methods: This was a propensity score–matched cohort study using province-wide multiple-linked administrative databases in Ontario, Canada. Patients with previous ischemic heart disease or heart failure who received bariatric surgery were matched on age, sex, heart failure history, and a propensity score to similar controls from a primary care medical record database in a 1:1 ratio. The primary outcome was the incidence of extended MACE (first occurrence of all-cause mortality, myocardial infarction, coronary revascularization, cerebrovascular events, and heart failure hospitalization). Secondary outcome included 3-component MACE (myocardial infarction, ischemic stroke, and all-cause mortality). Outcomes were evaluated through a combination of matching via propensity score and subsequent multivariable adjustment. Results: A total of 2638 patients (n=1319 in each group) were included, with a median follow-up time of 4.6 years. The primary outcome occurred in 11.5% (151/1319) of the surgery group and 19.6% (259/1319) of the controls (adjusted hazard ratio [HR], 0.58 [95% CI, 0.48–0.71]; P <0.001). The association was notable for those with heart failure (HR, 0.44 [95% CI, 0.31–0.62]; P <0.001; absolute risk difference, 19.3% [95% CI, 12.0%–26.7%]) and in those with ischemic heart disease (HR, 0.60 [95% CI, 0.48–0.74]; P <0.001; absolute risk difference, 7.5% [95% CI, 4.7%–10.5%]). Surgery was also associated with a lower incidence of the secondary outcome (HR, 0.66 [95% CI, 0.52–0.84]; P =0.001) and cardiovascular mortality (HR, 0.35 [95% CI, 0.15–0.80]; P =0.001). Conclusions: Bariatric surgery was associated with a lower incidence of MACE in patients with cardiovascular disease and obesity. These findings require confirmation by a large-scale randomized trial.

Third, 3 of the 7 included RCTs (Fig. 3 panel A) did not implement standard LRYGB, but a simplified laparoscopic mini-gastric bypass, 2 silastic ring-LRYGB, 7,8 and open RYGB, 9,10 which might reduce the generalizability of the results.In view of these issues, we argue that that the meta-analyses regarding remission of type 2 diabetes do not accurately reflect the existing evidence.