The oral glucose tolerance test reveals a high frequency of both impaired glucose tolerance and undiagnosed Type 2 diabetes mellitus in primary hyperparathyroidism

Diabet Med. 2002 Nov;19(11):958-61. doi: 10.1046/j.1464-5491.2002.00809.x.

Abstract

Aims: 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.

MeSH terms

  • Aged
  • Blood Glucose / analysis
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Diabetes Mellitus, Type 2 / etiology
  • Female
  • Glucose Intolerance / blood
  • Glucose Intolerance / diagnosis*
  • Glucose Intolerance / etiology
  • Glucose Tolerance Test
  • Humans
  • Hyperparathyroidism / complications
  • Hyperparathyroidism / metabolism*
  • Insulin / blood
  • Insulin Resistance
  • Male
  • Middle Aged

Substances

  • Blood Glucose
  • Insulin