Yung Lee, BHSc1, Aristithes Doumouras, MD, MPH, FRCSC1, James Yu, BHSc1, Karanbir Brar, BHSc2, Laura Banfield, MLIS, MHSc1, Scott Gmora, MD, FRCSC, FACS1, Mehran Anvari, MD, PhD, FRCSC, FACS1, Dennis Hong, MD, MSc, FRCSC, FACS1. 1McMaster University, 2University of Toronto
Introduction: We aim to conduct a systematic review and meta-analysis to critically evaluate the benefits and harms of bariatric surgery on Nonalcoholic fatty liver disease in patients with obesity. NAFLD has become one of the most common chronic liver diseases in the world, affecting 20–30% of the general population in Western countries and costing the US healthcare system $32 billion annually. There is a rapidly growing body of evidence demonstrating the complete resolution of NAFLD following the sustained weight loss induced by bariatric surgery.
Methods: MEDLINE, EMBASE, CENTRAL, and Web of Science were searched up to May 2018. Studies were eligible for inclusion if a study compared biopsy results of NAFLD before and after bariatric surgery in patients with obesity. Exclusion criteria were studies with <10 patients or cirrhosis. Primary outcomes were biopsy-confirmed resolution of NAFLD (steatosis, inflammation, ballooning degeneration, fibrosis) and NAFLD activity score (NAS); secondary outcome was worsening of NAFLD (liver side effects) and change in liver volume after surgery. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) to assess quality of evidence. Pooled proportions and mean differences (MD) were calculated using the random effects meta-analysis and Freeman-Tukey double arsine transformation. Heterogeneity was quantified using the I2 statistic and publication bias was assessed using a funnel plot.
Results: Among 1,695 studies identified, 32 cohort studies involving a total of 3,093 biopsies met the inclusion criteria. Bariatric surgery resulted in a biopsy-confirmed resolution of steatosis in 66% (95% Confidence Interval (CI), 56–75%), inflammation in 50% (95% CI, 35–64%), ballooning degeneration in 76% (95% CI, 64–86%), and fibrosis in 40% of patients (95% CI, 29–51%). NAS was significantly reduced after bariatric surgery (Mean Difference (MD) 2.39; 95% CI, 1.58–3.20; p<0.001). Liver volume by magnetic resonance imaging and showed significant reductions in liver volume 6 months after bariatric surgery (MD 469.35 cm3; 95% CI, 297.02–641.68, p<0.001). However, bariatric surgery resulted in new or worsening features of NAFLD such as fibrosis in 12% of patients (95% CI, 5–20%). The overall GRADE quality of evidence was very low.
Conclusions: Bariatric surgery performed on obese patients with NAFLD leads to complete resolution of NAFLD in a substantial proportion of patients. However, there is a minor chance of patients developing new or worsening histological features of NAFLD. High quality randomized controlled trials are needed to confirm the therapeutic benefits of bariatric surgery for NAFLD.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 91694
Program Number: P085
Presentation Session: Poster Session (Non CME)
Presentation Type: Poster