Effects of Sleeve Gastrectomy and Gastric Bypass on Postprandial Lipid Profile in Obese Type 2 Diabetic Patients: a 2-Year Follow-up

Bariatric surgery (BS) is known to favorably impact fasting lipid profile. Fasting and postprandial lipids were evaluated before and 2 years after BS in obese type 2 diabetic (T2DM) patients. Methods A prospective study was conducted in 19 obese T2DM patients: ten undergoing sleeve gastrectomy (SG) and nine undergoing Roux-en-Y gastric bypass (RYGB). Before and 2 years after BS, clinical parameters and the response of lipid and incretin hormones to a mixed meal (MM) were assessed. Results The two groups had similar characteristics at baseline.After BS, weight loss was similar in the two groups (p≤0.01). Fasting glucose, insulin, and triglycerides decreased while HDL cholesterol increased in a similar way (p<0.05); in contrast, fasting LDL cholesterol decreased only after RYGB (p<0.05). Post-meal glucose concentrations decreased while early insulin response significantly improved after both procedures (p<0.001 for both). Postprandial triglycerides decreased after both procedures (p<0.05) while postprandial LDL cholesterol decreased only after RYGB (p<0.05). Meal-GLP-1 increased postoperatively in both groups although to a greater extent after RYGB (p<0.001 vs. SG). GIP decreased after both procedures, especially after RYGB (p=0.003). At multivariate analysis, GLP-1 peak was the best predictor of LDL reduction (β=−0.552, p=0.039) while the improvement of HOMA-IR (β=0.574, p=0.014) and weight loss (β=0.418, p=0.036) predicted triglycerides reduction. Conclusions Both surgical procedures markedly reduce fasting and postprandial triglycerides and increase HDL cholesterol levels. LDL cholesterol decreases only after RYGB through a mechanism likely mediated by the restoration of GLP-1.