title: The role of beta-cell function and insulin sensitivity in the remission of type 2 diabetes after gastric bypass surgery.
abstract: BACKGROUND
  Bariatric surgery can induce remission in a high proportion of severely obese patients with type 2 diabetes mellitus (T2DM).
  
  
  OBJECTIVE
  Our objective was to investigate predictors and mechanisms of surgery-induced diabetes remission.
  
  
  METHODS
  Forty-three morbidly obese subjects (body mass index = 45.6 ± 5.0 kg/m(2)), 32 with T2DM and 11 nondiabetic [normal glucose tolerance (NGT)], participated at a clinical research center.
  
  
  METHODS
  Patients underwent Roux-en-Y gastric bypass.
  
  
  METHODS
  Diabetes remission and β-cell function were evaluated.
  
  
  RESULTS
  Subjects were tested before and 45 d and 1 yr after surgery. Weight decreased similarly in T2DM and NGT (-39 kg at 1 yr, P < 0.0001). Insulin sensitivity improved in both groups in proportion to the changes in body mass index but remained lower in T2DM than NGT (386 ± 91 vs. 479 ± 89 ml/min · m(2), P < 0.01). Based on glycosylated hemoglobin and oral glucose testing, diabetes had remitted in nine patients at 45 d and in an additional 16 at 1 yr. In T2DM, β-cell glucose sensitivity increased early after surgery but was no further improved and still abnormal at 1 yr [median, 48 (coefficient interval, 53) pmol/min · m(2) · mm vs. median, 100 (coefficient interval, 68) of NGT, P < 0.001]. Baseline β-cell glucose sensitivity was progressively worse in early remitters, late remitters, and nonremitters (median, 54[coefficient interval, 50] vs. median, 22[coefficient interval, 26] vs. median, 4[coefficient interval, 10] pmol/min · m(2) · mm) and, by logistic regression, was the only predictor of failure [odds ratio for bottom tertile = 7.9 (95% confidence interval = 1.2-51.9); P = 0.03].
  
  
  CONCLUSIONS
  In morbid obesity, Roux-en-Y gastric bypass causes rapid and profound metabolic adaptations; insulin sensitivity improves in proportion to the weight loss, and β-cell glucose sensitivity increases independently of weight loss. Over a period of 1 yr after surgery, diabetes remission depends on the starting degree of β-cell dysfunction.
authors.affiliation: Department of Internal Medicine, University of Pisa, Via Roma 67, 56100 Pisa, Italy. nannipi@ifc.cnr.it
authors.forename: M
authors.initials: M
authors.lastname: Nannipieri
authors.forename: A
authors.initials: A
authors.lastname: Mari
authors.forename: M
authors.initials: M
authors.lastname: Anselmino
authors.forename: S
authors.initials: S
authors.lastname: Baldi
authors.forename: E
authors.initials: E
authors.lastname: Barsotti
authors.forename: D
authors.initials: D
authors.lastname: Guarino
authors.forename: S
authors.initials: S
authors.lastname: Camastra
authors.forename: R
authors.initials: R
authors.lastname: Bellini
authors.forename: R D
authors.initials: RD
authors.lastname: Berta
authors.forename: E
authors.initials: E
authors.lastname: Ferrannini
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D012074:Remission Induction; D015431:Weight Loss / Q000502:physiology
chemical_list: D001786:Blood Glucose; D007328:Insulin