Reduced insulin secretion in normoglycaemic patients with β-thalassaemia major

• Published in: Diabetic medicine Vol. 23; no. 12; pp. 1327 - 1331
• Main Authors: Angelopoulos, N. G., Zervas, A., Livadas, S., Adamopoulos, I., Giannopoulos, D., Goula, A., Tolis, G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2006; Blackwell
• Subjects: Adult; Anemias. Hemoglobinopathies; beta-Thalassemia - blood; beta-Thalassemia - complications; Biological and medical sciences; Blood Glucose - metabolism; C-Peptide - metabolism; Case-Control Studies; Diabetes Mellitus - blood; Diabetes Mellitus - etiology; Diabetes Mellitus - metabolism; Diabetes. Impaired glucose tolerance; Diseases of red blood cells; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; fasting glycaemia; Female; glucose tolerance; Glucose Tolerance Test; Hematologic and hematopoietic diseases; Homeostasis; homeostasis model assessment; Humans; Insulin - deficiency; Insulin - metabolism; Insulin Secretion; Male; Medical sciences; Models, Biological; β-thalassaemia major; Endocrinopathy; Human; fasting glycaemia; Hemoglobinopathy; Pancreatic hormone; Secretion; Diabetes mellitus; Homeostasis; Tolerance; Hemopathy; Glucose; Insulin; Genetic disease; Hemolytic anemia; β-Thalassemia; β-thalassaemia major; Models; glucose tolerance; Fast; Glycemia; homeostasis model assessment
• DOI: 10.1111/j.1464-5491.2006.01988.x
• ISSN: 0742-3071

Aims  To assess insulin sensitivity and secretion in the fasting state in regularly transfused patients with β‐thalassaemia major with normal glucose response during an oral glucose tolerance test and to estimate its possible relation to iron overload. Methods  We measured fasting glucose, insulin and C‐peptide levels in 24 patients with β‐thalassaemia major and 18 control subjects matched for age and body mass index. Insulin sensitivity and insulin release index were calculated according to the homeostasis model assessment (HOMA). Correlations with age, body mass index and serum ferritin were also calculated. Results  Fasting glucose levels in patients were increased compared with control subjects (5.5 ± 0.12 vs. 4.7 ± 0.13 mmol/l, mean ± sem, P < 0.001). Pancreatic B‐cell insulin secretion in the fasting state (estimated by SCHOMA) was lower in thalassaemic patients (SCHOMA 88.5 ± 11.11 vs. 184.3 ± 23.72 in control subjects, P < 0.001). Patients were then divided into those with impaired (IFG) and normal (NFG) fasting glucose. SCHOMA was higher in the patients with NFG compared with those with IFG patients (110.6 ± 17.63 vs. 66.3 ± 10.88, respectively, P < 0.05) but estimated insulin sensitivity (ISIHOMA) was similar. Plasma values of C‐peptide correlated positively with ferritin (r = 0.42, P = 0.04) and SCHOMA (r = 0.45, P = 0.02) and negatively with ISIHOMA (r = −0.43, P = 0.03). Conclusions  These results support the concept that impaired B‐cell function, as reflected by a reduction in the insulin secretion index, is present in β‐thalassaemic patients with normoglycaemia before changes in oral glucose tolerance tests are apparent.