title: The oral glucose tolerance test reveals a high frequency of both impaired glucose tolerance and undiagnosed Type 2 diabetes mellitus in primary hyperparathyroidism.
abstract: OBJECTIVE
  To evaluate the frequency of impaired glucose tolerance (IGT)and undiagnosed diabetes mellitus together with the indices of insulin resistance (IR) in primary hyperparathyroidism (pHPT).
  
  
  METHODS
  Out of 105 consecutive pHPT patients (F/M 78/27, asymptomatic/symptomatic 68/37, age (mean +/- s.d.) 60.7 +/- 12.7 years,body mass index 25.2 +/- 3.8 kg/m2, ionized calcium (iCa) 1.49 +/- 0.16 mmol/l,parathormone 200.4 +/- 233.9 pg/ml),59 without known diabetes mellitus and controls (n = 60) underwent an oral glucose tolerance test (OGTT, 75 g os). As indices of IR, homeostasis model assessment (HOMAIR)or OGTT data (insulin sensitivity index composite (ISI comp)) were evaluated.
  
  
  RESULTS
  In pHPT the prevalence of IGT (mean, 95% confidence intervals (CI), 40.7%, 27.8-53.6) was higher than in controls (25.0%, 13.7-36.3, P < 0.03). Similarly,the prevalence of undiagnosed diabetes mellitus was higher in pHPT(15.3%, 5.8-24.7) than in controls (5.0%, 0-10.7, P < 0.05). Moreover,the prevalence of IGT and undiagnosed diabetes was higher in pHPT than that previously reported in the general population of Northern Italy(8.5% and 3.2%, respectively). The indices showed that insulin resistance was higher in pHPT than in controls: HOMAIR (median, 95% CI,2.6, 2.5-3.9 vs. 1.7, 1.6-2.5, respectively; P < 0.003); ISI comp (3.5, 3.4-4.6 vs. 5.1, 4.9-7.2, respectively; P < 0.002).
  
  
  CONCLUSIONS
  Our data in a large and modern day pHPT series, with a preponderance of asymptomatic patients, confirm increased insulin resistance and pre-valence of IGT and undiagnosed diabetes.
authors.affiliation: Division of Endocrinology, Az OspedalieraS. Croce e Carle, Cuneo, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Procopio
authors.forename: G
authors.initials: G
authors.lastname: Magro
authors.forename: F
authors.initials: F
authors.lastname: Cesario
authors.forename: A
authors.initials: A
authors.lastname: Piovesan
authors.forename: A
authors.initials: A
authors.lastname: Pia
authors.forename: N
authors.initials: N
authors.lastname: Molineri
authors.forename: G
authors.initials: G
authors.lastname: Borretta
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D005951:Glucose Tolerance Test; D006801:Humans; D006961:Hyperparathyroidism / Q000150:complications / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D007328:Insulin