Reoperative bariatric surgery for treatment of type 2 diabetes mellitus

Primary bariatric surgery has been proven to be effective in weight loss and improvement of weight-related metabolic co-morbidities. However, a small proportion of patients after bariatric surgery either have persistent hyperglycemia or relapse after initial remission of their metabolic disease. Revisional bariatric surgery has been evaluated extensively for weight recidivism and postoperative complications. However, there has not been any high-level evidence validating the utility of revisional bariatric surgery on recurrent metabolic diseases, especially diabetes. In this review of 30 studies, we aimed to summarize the evidence and determine whether revisional surgery can have a positive impact on metabolic diseases that were not reversed by initial bariatric intervention. Overall, 14-38% of patients had residual diabetes at the time of revisional surgery. Depending on the index surgery and subsequent reconstruction, revisions induced 20-80% additional excess weight loss, or further decrease of body mass index by 10-30%. Improvement of diabetes was seen in 65-100% of patients. Specifically, conversion to Roux-en-Y gastric bypass (RYGB) yielded improvement of diabetes in 79%, 72%, and 62% of patients who previously had vertical banded gastroplasty (VBG), adjustable gastric banding (AGB), or sleeve gastrectomy (SG), respectively. Converting AGB to SG improved diabetes in 65% of patients, and SG to duodenal switch improved diabetes in 79% of patients. Revision of the gastric pouch or stoma in RYGB yielded improvement of diabetes in 79% of patients. Further clinical and mechanistic research is needed to better delineate the role of revisional bariatric surgery in patients with residual metabolic disease.