The preoperative use of restricted energy diets to reduce liver volume and liver fat content and improve postoperative outcome in obsese patients scheduled for bariatric surgery: a systematic review and meta-analysis

[摘要] English: Bariatric surgery is recognized as the most effective treatment modality for obesity. Since obesity levels are on the increase both locally and globally, it is expected that the number of procedures performed will increase in the future. A practical limitation to performing bariatric surgery is the fact that operating space within the abdomen is limited by excessive layers of abdominal fat and the presence of a large, fatty liver. Fat deposition in the liver is common in obesity. Reducing the fatty deposits in the liver can reduce the size of the liver, thereby in theory it can also reduce the complexity of the surgical technique. A number of individual trials have evaluated the potential of energy restriction for a period of two to 12 weeks before surgery to reduce the liver size and liver fat content. Data from these trials are promising, but individually does not provide sufficient evidence to justify evidence-based recommendation in favour of the use of restricted energy diets prior to surgery. This review combines the findings of individual trials in order to provide an evidence-base for such practice. At the time of protocol development, no systematic review has been published to document the benefits of energy restricted diets in reducing liver size and fat content in obese patients who are undergoing bariatric surgery for weight loss. A systematic literature search was undertaken to identify studies published between 1980 and 2012 on the research topic. Studies were evaluated and eliminated based on inclusion and exclusion criteria so that a total ofnine studies were included in the review. Study design and methodology were appraised, and results of individual trials compared and combined where appropriate in order to provide a comprehensive overview of current literature in the form of a narrative systematic review. A meta-analysis was not possible due to differences in reporting. Results indicated that preoperative diet restriction effectively reduces liver volume by decreasing the liver fat content. It was however not clear if these changes can be directly linked to reduction in operative complexity, reduction in intra-operative blood loss, or reduction in duration of surgery. Randomized, blinded trials are needed to confirm if a relationship exists. One well-designed study indicated reduction in post-operative complications. In conclusion, this review found that preoperative restricted energy diets used for an acute period before surgery can significantly reduce liver volume and fat content in obese patients, and may translate to improved patient outcome.

[发布机构] University of the Free State