Background: Bariatric surgery has been shown to decrease insulin requirements even before significant weight loss has occurred. We report a patient with marked improvement in glycemic control despite modest weight loss post bariatric surgery.
Case presentation: A 47 years old Chinese man with obesity (weight 90 kg, BMI 31.2), hypertension, hyperlipidemia and type 2 diabetes mellitus diagnosed in 2005 is on follow up with our endocrine clinic. Despite compliance to more than 200 units of insulin a day, his glycemic control remained poor with a HbA1c persistently more than 10%. This is largely attributed to insulin resistance and dietary indiscretion. He underwent laparoscopic Roux-en-Y gastric bypass in mid 2012. Post-operatively, he experienced a total of 14 kg weight loss over 6 months. His HbA1c fell from 11.4 to 6.7% (within 4 months). All his diabetic and cholesterol lowering medications have been stopped.
Discussion: Resolution or remission of T2DM has been well documented following bariatric surgery in obese patients. This phenomenon is well reported after significant weight reduction. In this case study, the actual achieved weight loss was modest (15.6 vs 45.1% estimated weight loss in other demographically similar subjects), yet the glycemic control was comparable to similar subjects who lost much more weight in the same time period. This rapid reversal of hyperglycemia is not well understood and could partly be explained by improved beta cell function and insulin sensitivity following malabsorptive bariatric surgery. These outcomes have been linked to enhanced incretin responses along the gastroenteroinsular axis facilitating these improvements in glucoregulation.