Evolution of OGTT in patients with beta-thalassaemia major in relation to chelation therapy

Glucose metabolism disturbances are frequently reported among patients with beta-thalassaemia major on conventional treatment consisted of regular blood transfusions and adequate chelation treatment. Aim of this study was to evaluate the evolution of oral glucose tolerance test (OGTT) in thalassaemic patients in relation to their chelation treatment. Data from two OGTTs performed with an interval of 2 years were studied retrospectively. Patients considered eligible for this study were those who maintained unchanged chelation treatment and did not receive any anti-diabetic agent during the last 2 years. Thirty-one patients (16 M and 15 F) were enrolled with a mean age of 23.73+/-4.23 years at the end of the study. Patients were divided into three groups concerning chelation treatment. First group was receiving deferoxamine (DFO) by an 8-hourly subcutaneous infusion five-six times a week, second group was chelated with deferiprone (DFP) at a daily dose of 75 mg/kg orally and the third group was receiving combined therapy with DFO (3 days/week) and DFP (daily). At the time of the first OGTT, 26 patients (84%) were found to have normal OGTT; three of them showed an impaired glucose tolerance during second test (one was chelated with DFP and two were receiving combined therapy). None of the five patients with impaired glucose metabolism during the first test became diabetic. On contrary, one patient receiving combined therapy managed to normalize his second OGTT. In contrast with the overall trend of a deteriorating glucose tolerance in the whole patient series, the group receiving combined therapy managed to increased beta-cell function index and decreased insulin resistance index, although not statistically significant when compared to other groups. Further studies are needed to support these preliminary results.