Predicting the Glycemic Response to Gastric Bypass Surgery in Patients With Type 2 Diabetes

  1. Wei-Jei Lee, PHD6
  1. 1Baker IDI Heart & Diabetes Institute, Melbourne, Victoria, Australia
  2. 2Primary Care Research Unit, Monash University, Melbourne, Victoria, Australia
  3. 3Department of Internal Medicine, National Taiwan University Hospital, Taipei, Republic of China
  4. 4Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Republic of China
  5. 5Department of Internal Medicine and
  6. 6Department of Surgery, Min-Sheng General Hospital, Taiwan, Republic of China
  1. Corresponding author: Wei-Jei Lee, wjlee_obessurg_tw{at}


OBJECTIVE To find clinically meaningful preoperative predictors of diabetes remission and conversely inadequate glycemic control after gastric bypass surgery. Predicting the improvement in glycemic control in those with type 2 diabetes after bariatric surgery may help in patient selection.

RESEARCH DESIGN AND METHODS Preoperative details of 154 ethnic Chinese subjects with type 2 diabetes were examined for their influence on glycemic outcomes at 1 year after gastric bypass. Remission was defined as HbA1c ≤6%. Analysis involved binary logistic regression to identify predictors and provide regression equations and receiver operating characteristic curves to determine clinically useful cutoff values.

RESULTS Remission was achieved in 107 subjects (69.5%) at 12 months. Diabetes duration <4 years, body mass >35 kg/m2, and fasting C-peptide concentration >2.9 ng/mL provided three independent preoperative predictors and three clinically useful cutoffs. The regression equation classification plot derived from continuous data correctly assigned 84% of participants. A combination of two or three of these predictors allows a sensitivity of 82% and specificity of 87% for remission. Duration of diabetes (with different cutoff points) and C-peptide also predicted those cases in which HbA1c ≤7% was not attained. Percentage weight loss after surgery was also predictive of remission and of less satisfactory outcomes.

CONCLUSIONS The glycemic response to gastric bypass is related to BMI, duration of diabetes, fasting C-peptide (influenced by insulin resistance and residual β-cell function), and weight loss. These data support and refine previous findings in non-Asian populations. Specific ethnic and procedural regression equations and cutoff points may vary.

  • Received April 24, 2012.
  • Accepted July 2, 2012.

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  1. Diabetes Care
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