A prospective 4-year study of insulin resistance and adipokines in morbidly obese diabetic and non-diabetic patients after gastric banding.

Abstract

IntroductionThere are insufficient data regarding the changes in adipokine levels after laparoscopic adjustable gastric banding (LAGB) in diabetic and non-diabetic patients and their effects on insulin resistance and type 2 diabetes remission.AimTo assess leptin, adiponectin, and insulin resistance changes after LAGB in diabetic and non-diabetic morbidly obese patients.Material and methodsOne hundred and three patients (37 with and 66 without type 2 diabetes) underwent LAGB from January 2009 to January 2010. Glycated hemoglobin, insulin, adipokine levels and insulin resistance were evaluated preoperatively, and 1 and 4 years after LAGB.ResultsThe mean patient age was 45.9 ±11.7 years and mean preoperative body mass index was 47.5 ±7.3 kg/m2. A total of 80 of 103 patients (77.6%) completed the 4-year follow-up. After 4 years the mean excess weight loss was 38.8% and 39.5% in diabetic and non-diabetic patients respectively. Leptin levels decreased significantly in both groups at 1 year, but after 4 years this was noted only in non-diabetic patients. After 1 year adiponectin levels increased significantly only in non-diabetic patients (p = 0.003) and remained almost the same at 4 years. A significant decrease in insulin resistance was noted in both groups 1 year after LAGB and diabetes remission was observed in 23 (62.1%) patients. There was a negative correlation between preoperative insulin resistance and adiponectin levels throughout the follow-up period. Leptin levels positively correlated with BMI throughout the study period (baseline r = 0.45; p < 0.001; after 1 year r = 0.71; p < 0.001; after 4 years r = 0.68; p < 0.001). There was no significant correlation between leptin and adiponectin concentrations preoperatively or after 1 year; however, at 4 years it was significant (r = 0.27; p < 0.02).ConclusionsThe most significant metabolic changes occurred within 1 year after LAGB. The 4-year follow-up revealed stabilization in metabolic indices rather than significant improvement.

The leptin to adiponectin ratio (LAR) is reduced by sleeve gastrectomy in adults with severe obesity: a prospective cohort study

“…We found that the reductions in LAR were driven primarily by an increase in adiponectin rather than a reduction in leptin, and these changes were proportional to the reduction in weight after surgery, consistent with the Unamuno study. The changes we observed in leptin and adiponectin concentrations were less than those described after bypass bariatric surgery 3,6,7 and are more consistent with those previously described after banding 8 .…”

“…A key limitation of our study is its modest size (reflected in the borderline statistical significance of the reduction in LAR, for example), but the effects of bariatric surgery on metabolic outcomes and cardiovascular disease risk tend to be so profound that even in randomised controlled trials, surgical interventions require population sizes 2 that are orders of magnitude smaller than those in drug 26 or lifestyle intervention trials 27 . Our cohort size is similar to other surgical studies 3 , 6 – 8 , 15 and our findings around the correlation between weight loss and reduced LAR are statistically robust. Rather than using LAR as the only index of insulin sensitivity, future studies could also examine indices related to fasting glucose and insulin (such as the homeostasis model assessment, HOMA 28 ), in order to strengthen causal inference on the impact of bariatric interventions on insulin sensitivity.…”

“…We have shown that in a predominantly white cohort of adults with severe obesity who underwent laparoscopic sleeve gastrectomy, there was a substantial reduction in the LAR after 12 months, which may indicate an increase in insulin sensitivity. While several studies have measured leptin or adiponectin separately in patients after bariatric surgery 3 , 6 – 8 , 15 , we are aware of only one other study by Unamuno et al that has considered them together as a ratio and as an indicator of adipocyte dysfunction 16 . Ours is the first study to consider these adipokines as a ratio in patients undergoing laparoscopic sleeve gastrectomy.…”

“…Conversely, adiponectin reduces circulating free fatty acids by increasing tissue fat oxidation: Adiponectin levels tend to be lower in individuals with obesity 14 . Several studies have described reductions in leptin and increases in adiponectin in adults with severe obesity undergoing bariatric surgery 3 , 6 – 8 , 15 . Recently, investigators described changes in the adiponectin: leptin ratio (ALR) in a cohort of 25 Spanish adults with type 2 diabetes who underwent Roux-en-Y gastric bypass 16 .…”

“…Bariatric surgery to treat severe obesity leads to significant improvements in diabetes control 2 , cardiovascular risk 3,4 , microalbuminuria 5 and systemic inflammation 6 . However, the influence of bariatric surgery on insulin sensitivity is not well defined 7,8 , partly because quantifying insulin sensitivity can be challenging. For example, the hyperinsulinaemic-euglycaemic clamp allows precise measurement of insulin sensitivity in muscle and liver 9 but is a technically elaborate and expensive technique that is only available in specialized research units.…”