Long-term follow-up of β-transfusion-dependent thalassemia (TDT) normoglycemic patients with reduced insulin secretion to oral glucose tolerance test (OGTT): A pilot study

Vincenzo de Sanctis*, Ashraf T. Soliman, Shahina Daar, Ploutarchos Tzoulis, Salvatore Di Maio, Christos Kattamis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To study the endocrine pancreas' function in transfusion-dependent β-thalassemia (β-TDT) patients with a normal glucose tolerance test (NGT) and hypoinsulinemia. In addition, the prospective long-term follow-up using an annual oral glucose tolerance test (OGTT) to detect any abnormality of glucose metabolism. Patients and methods: Seven β-TDT patients (mean age 22.4 ± 4.2 years) with NGT and inadequate insulin response (hypoinsulinemia) to OGTT were referred for a second opinion to an Italian Centre. Results: The first-phase insulin response (FPIR), expressed as the sum of 1 and 3 minutes insulin, to intravenous glucose tolerance test (IVGTT), was between the 1st and 3rd percentile in two patients and between the 3rd and 10th percentile in five. The results were not associated with β-cell autoimmunity. After 43 ± 26 months (range 11 - 80 months) of follow-up, two patients developed impaired glucose tolerance (IGT), three both IGT and impaired fasting glucose (IFG) and two overt diabetes mellitus (DM). Interestingly, the patients who developed DM had, at baseline, the lowest value of the insulinogenic index (IGI: 0.08 and 0.25), defined as the ratio of the increment of plasma insulin to plasma glucose during the first 30 minutes after OGTT. Moreover, a significant correlation was found between the IGI at baseline and at follow-up in the patients who developed IGT with or without IFG (R= 0.927; P: 0.023). A significant reduction of Matsuda insulin sensitivity index (ISIM) and Insulin Secretion-Sensitivity Index-2 (ISSI-2) was documented in the study cohort at the diagnosis of IFG, IGT, and DM. There was a significant inverse correlation between ISSI-2 and area under the curve plasma glucose (AUC-PG). Conclusions: These data demonstrated, for the first time, progressive deterioration in glucose homeostasis in β-TDT subjects with NGT and hypoinsulinemia and that the ISSI-2 index may be a valuable parameter to identify patients at high risk for developing glucose dysregulation.

Original languageEnglish
Article numbere2021021
JournalMediterranean Journal of Hematology and Infectious Diseases
Volume13
Issue number1
DOIs
Publication statusPublished - Mar 1 2021
Externally publishedYes

Keywords

  • Follow-up
  • Glucose tolerance abnormalities
  • Hypoinsulinemia
  • Insulin resistance
  • Intravenous glucose tolerance test
  • Iron overload
  • Oral glucose tolerance test
  • Transfusion-dependent β-thalassemia

ASJC Scopus subject areas

  • Hematology
  • Infectious Diseases

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