Insulin dependent diabetes in thalassaemia.

Diabetes mellitus was observed in 29 of 448 patients with thalassaemia major attending seven Italian centres. Twelve patients, at onset of clinical diabetes, presented with an asymptomatic glycosuria, 13 with ketosis, and four with ketoacidosis. All were diagnosed after 1979, at a mean age of 17 years. Mean age at diagnosis of diabetes was lower in patients born in the last two decades. In these patients transfusions were started at a younger age and pre-transfusion haemoglobin concentration, serum ferritin concentration, incidence of liver disease, and the presence of a family history of diabetes were higher than in patients born previously. Although 27 (93%) cases had iron chelating treatment the mean serum ferritin concentration was 5600 micrograms/l; 25 (92%) of these patients had signs of liver impairment. The determination of C peptide in 10 patients showed a wide variation in pancreatic beta cell function, and insulin requirements ranged between 0.15 and 1.72 U/kg body weight. Metabolic control was generally poor. The onset of diabetes mellitus was followed in most patients by the appearance of other endocrine or cardiac complications, or both. Fourteen patients died within three years of presenting with overt diabetes. Haemosiderosis, liver infections, and genetic factors seemed to be crucial in diabetes development. Thalassaemic patients developing clinical diabetes mellitus are at high risk for other complications and should be strictly monitored, especially for thyroid impairment.