Excessive weight can bring with it many medical problems, including insulin resistance and often type 2 diabetes. Bariatric surgery for severely obese patients leads to weight loss and improves insulin sensitivity.
In a study published in the current issue of The American Journal of Medicine, researchers from the State University of Campinas, São Paulo, Brazil; Catholic University, Rome, Italy; and the University of Pisa, Italy, found that the degree of improvement depended on the surgical technique used, comparing biliopancreatic diversion to gastric bypass.
Writing in the article, Elza Muscelli, MD, of the State University of Campinas, states, "The striking finding of the present study is that major weight loss (average of 53 kg) led to different gains in insulin sensitivity depending on the type of surgery. Although the degree and time course of weight reduction were almost identical in the two surgical groups, patients who had undergone biliopancreatic diversion achieved levels of insulin sensitivity that were more than double those of patients who had undergone gastric bypass. Further, these levels were higher than those of lean controls."
Eighteen nondiabetic patients with severe obesity and 20 sex- and age-matched lean subjects underwent metabolic studies, including measurement of insulin sensitivity. The obese patients then underwent either gastric bypass, which restricts food intake by making the stomach very small, or biliopancreatic diversion, which shortens the small intestine and reduces absorption of fats. Patients were restudied at 5 to 6 months and again at 16 to 24 months postsurgery.
Dr. Muscelli concludes, "Bariatric surgery is increasingly considered for the treatment of morbidly obese patients who have serious comorbidity or in whom medical or behavioral weight reduction therapies are ineffective. In the present study, the physiological difference between gastric bypass and biliopancreatic diversion was exploited to highlight the link between lipid malabsorption and insulin action. However, the choice of the optimal therapeutic strategy in these patients depends on a risk/benefit algorithm to be assessed in each patient."