Diabetes in Thalassaemia

• It is believed to be due to damage of pancreatic b cells caused by iron overload. There is reduced insulin secretion in normoglycaemic β thalassaemia major patients.

• The appearance of DM in thalassaemia patients may be due to a combination of insulin resistance and insulin deficiency caused by either exhaustion of β cells, iron deposition in islet cells or a combination of these factors.

• Overt DM in thalassaemia major patients is preceded by a long period of insulin resistance and hyperinsulinaemia.

• Understanding the underlying cause of diabetes in an individual is essential for logical treatment decisions

Treatment

• The early and adequate use of iron chelation can prevent DM and major endocrinopathies.

• In thalassaemias with IGT, the condition may improve with a strict diabetic diet, weight reduction where applicable and intensive iron chelation

Insulin

• In thalassaemia patients with DM, insulin treatment is normally required but metabolic control may be difficult to achieve.

• Insulin requirement (0.15 - 1.72 U/kg) varies due to a wide variation in pancreatic b cell function as determined by C-peptide level

Oral Hypogycaemic agents

• The role of oral hypoglycaemic agents remains to be fully determined

• Where hyperinsulinism is insufficiently managed by diet alone, acarbose may be a useful first-line therapy for glycaemic control

• There are reports on the successful use of sulphonylureas and acarbose. Sulphonylureas (e.g. glibenclamide, gliclazide, glimepiride) lower blood glucose by increasing insulin release from pancreatic ß-cells.

• For type 2 diabetes, metformin is the first choice treatment but there is little research on its use in thalassaemia.

References

1. http://www.latunisiemedicale.com/article-medicale-tunisie.php?article=1277
2. CPD Management of Transfusion Dependent Thalassaemia
3. Guidelines for the Clinical Management of Thalassaemia, 2^nd edition.
4. Endocrinological Problems in Adult Thalassemia Patients. Available on-line at web site http://medicaljournal.gazi.edu.tr/