Improved Insulin Sensitivity After Gastric Bypass Correlates with Decreased Total Body Fat, But Not with Changes in Free Fatty Acids

Lawrence Tabone, MD, Khoo Chin Meng, MD, Philip Omotosho, MD, Alfonso Torquati, MD, MSCI

Duke University, Department of Surgery

INTRODUCTION: Increased plasma free fatty acids (FFA) are considered one of the key elements in the pathogenesis of insulin resistance and type 2 diabetes (T2DM). We hypothesize that, in diabetic patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB), a postoperative decrease in FFA will correlate with improved insulin sensitivity and remission of T2DM. To test this hypothesis, a prospective cohort study was completed.

METHODS AND PROCEDURES: 30 obese (BMI>35) patients with a diagnosis of T2DM were studied preoperatively and 12 months after LRYGB. Studies included intravenous glucose tolerance test (IVGTT), total body composition by DEXA and plasma levels of FFA. Insulin sensitivity analysis (Si) from the IVGTT was estimated from minimal model analysis. Pre- and postoperative variables were compared using a paired sample t-test while relationships between changes in variables were determined with Pearson’s correlation test.

RESULTS: Twelve months after RYGB the study population showed a significant decrease in body mass index (P = 0.001), plasma FFA (P = 0.03), total body fat (P = 0.03), and lean body fat (P = 0.04) with a significant increase in Si (P = 0.001). Postoperative changes in insulin sensitivity, measured by Si, significantly correlated (Pearson’s r = -0.53, P=0.01) with change in total body fat but not with changes in plasma FFA (Pearson’s r = -0.22, P= 0.31).

CONCLUSION: Our study challenges the established notion that insulin resistance is mediated to a significant degree by changes in plasma FFA concentration. Instead, changes in adiposity and consequently changes in adipokines release can be the key players in determining remission of T2DM after RYGB.

Session: Poster Presentation

Program Number: P023

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