Published in:
01-01-2015 | Original Contributions
Surgical Treatment of Type 2 Diabetes in Subjects with Mild Obesity: Mechanisms Underlying Metabolic Improvements
Published in: Obesity Surgery | Issue 1/2015
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Background
This study aims to assess the clinical and physiological effects of Roux-en-Y gastric bypass (RYGBP) on type 2 diabetes associated with mild obesity (body mass index [BMI] 30–34.9 kg/m2) over 24 months postsurgery.
Methods
In this prospective trial, 36 mildly obese subjects (19 males) with type 2 diabetes using oral antidiabetic drugs with (n = 24) or without insulin (n = 12) underwent RYGBP. Follow-up was conducted at baseline and 3, 6, 12, and 24 months postsurgery. The following endpoints were considered: changes in HbA1c, fasting glucose and insulin, antidiabetic therapy, BMI, oral glucose insulin sensitivity [OGIS, from meal tolerance test (MTT)], beta-cell secretory function [ΔCP(0–30)/ΔGlu(0–30) (ΔC-peptide/Δglucose ratio, MTT 0–30 min), disposition index (DI = OGIS ⋅ ΔCP(0–30)/ΔGlu(0–30)], glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) [incremental area under the curve (AUCi)], adiponectin, C-reactive protein, and lipids.
Results
All subjects achieved normal-to-overweight BMI after 3 months. Over 24 months, 31/36 (86 %) subjects presented HbA1c <7 % [complete and partial remission of diabetes in 9/36 (22 %) and 1/36 (3 %), respectively]. Since 3 months postsurgery, improvements were observed in OGIS [290 (174) to 373 (77) ml/min/m2, P = 0.009], ΔCP(0–30)/ΔGlu(0–30) [0.24 (0.19) to 0.52 (0.34) ng/mg, P = 0.001], DI [7.16 (8.53) to 19.8 (15.4) (ng/mg) (ml/min/m2), P = 0.001], GLP-1 AUCi [0.56 (0.64) to 3.97 (3.86) ng/dl ⋅ 10 min ⋅ 103, P = 0.000], and GIP AUCi [30.2 (12.6) to 27.0 (20.2) ng/dl ⋅ 10 min ⋅ 103, P = 0.004]. At baseline and after 12 months, subjects with diabetes nonremission had longer diabetes duration, higher HbA1c, lower beta-cell secretory function, and higher first 30-min GIP AUCi, compared with those with remission.
Conclusions
RYGBP improves the glucose metabolism in subjects with type 2 diabetes and mild obesity. This effect is associated with improvement of insulin sensitivity, beta-cell secretory function, and incretin secretion.