title: Association between the preoperative fasting and postprandial C-peptide AUC with resolution of type 2 diabetes 6 months following bariatric surgery.
abstract: OBJECTIVE
  Bariatric surgery results in the remission of type 2 diabetes mellitus (T2DM) in morbidly obese subjects. The aim of the study was to investigate the predictive value of both static and dynamic measures of C-peptide in relation to T2DM resolution 6 months after bariatric surgery regardless of the operation type.
  
  
  RESULTS
  A non-randomized prospective study of 24 participants with T2DM undergoing bariatric surgery. Measurements of fasting and 2-hour plasma glucose, insulin, C-peptide and measures of insulin sensitivity were recorded temporally during an oral glucose tolerance test pre-operatively and 6 months post-operatively. A responder was defined with a fasting glucose <5.6 mmol/L and HbA1c <6.0% postoperatively. Within the sample there were 11 responders and 13 non-responders at 6 months. There was a significant difference in the duration of diabetes between the groups. Fasting C-peptide (P≤0.05) and 2-hour C-peptide (P≤0.05) were higher in responders compared to non-responders. Significantly higher C-peptide levels were observed preoperatively at all time points for responders, with significantly higher area under the curve (AUC0-60 and AUC0-120). Using the lower quartiles for C-peptide levels, both fasting C-peptide (>2.5 ng/mL [0.83 nmol/L]) and 2-hour C-peptide (>5.2 ng/mL [1.73 nmol/L]) had a sensitivity and negative predictive value of 100% to predict T2DM remission. Logistic regression showed that C-peptide, duration of diabetes and BMI were associated with response. The area under the ROC curve was 0.94 and a regression model predicted diabetes remission with a sensitivity of 85.7% and a specificity of 88.9%.
  
  
  CONCLUSIONS
  This study demonstrated that static (fasting) and dynamic (AUC, 2-hour) C-peptide measurements predict T2DM resolution 6 months following bariatric surgery. This work provides insight into C-peptide dynamics as a predictor of response to bariatric surgery.
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK; Department of Diabetes and Endocrinology, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK. Electronic address: mallipedhi@doctors.org.uk.
authors.forename: Akhila
authors.initials: A
authors.lastname: Mallipedhi
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK; Department of Diabetes and Endocrinology, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK.
authors.forename: Thinzar
authors.initials: T
authors.lastname: Min
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Prior
authors.affiliation: Department of Diabetes and Endocrinology, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: MacIver
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Steve D
authors.initials: SD
authors.lastname: Luzio
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Gareth
authors.initials: G
authors.lastname: Dunseath
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Bracken
authors.affiliation: Swansea Trial Unit, College of Medicine, Institute of Life Sciences 2, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Saiful
authors.initials: S
authors.lastname: Islam
authors.affiliation: Welsh Institute of Metabolic and Obesity Surgery, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Barry
authors.affiliation: Welsh Institute of Metabolic and Obesity Surgery, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK.
authors.forename: Scott
authors.initials: S
authors.lastname: Caplin
authors.affiliation: Diabetes Research Group, Institute of Life Sciences, Swansea University, Swansea SA2 8PP, UK; Department of Diabetes and Endocrinology, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK; Welsh Institute of Metabolic and Obesity Surgery, Morriston Hospital ABM University Health Board, Swansea SA6 6NL, UK.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Stephens
mesh_terms: D000328:Adult; D019540:Area Under Curve; D002096:C-Peptide / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D057234:Preoperative Period; D011446:Prospective Studies
chemical_list: D002096:C-Peptide
keywords: Area under curve; Bariatric surgery; C-peptide; Insulin; Type 2 diabetes