Multicentre study on prevalence of endocrine complications in thalassaemia major. Italian Working Group on Endocrine Complications in Non-endocrine Diseases.

OBJECTIVE: Thalassaemia major is a common and serious medical problem, worldwide. However, there are few data concerning the various endocrine disorders which occur in this condition. We have surveyed 25 Italian centres in order to establish the prevalences and times of onset of endocrine disorders in patients with beta-thalassaemia major. PROJECT AND PATIENTS: A questionnaire specifically designed to investigate the prevalences of endocrinopathies was sent to 25 paediatric and haematology departments. The following data were recorded in the questionnaire: sex, age, height and weight, pubertal status according to Tanner's classification, history of secondary amenorrhoea, type of endocrinopathy and hormone levels at diagnosis, associated complications, serum ferritin level, liver enzymes (ALT) and compliance with treatment.

RESULTS: An analysis of data from 1861 patients showed that failure of puberty was the major clinical endocrine problem and was present in 51% of boys and 47% of girls, all over the age of 15 years. Secondary amenorrhoea was recorded in 23% of patients (mean age 18.3 years), primary hypothyroidism in 6.2% (mean age 15.8 years), insulin dependent diabetes mellitus in 4.9% (mean age 18.1 years) and hypoparathyroidism in 3.6% of the patients (mean age 18.7 years). At present, the majority are in the second or third decades of life. The prevalences of hypothyroidism, insulin dependent diabetes mellitus and hypoparathyroidism differed in the various centres, whereas the frequency of pubertal disorders was very similar.

CONCLUSIONS: Our study has demonstrated several points. Endocrine evaluation in thalassaemic patients must be carried out regularly, especially in those patients over the age of 10 years with iron overload and poor compliance with chelation therapy. The prevalences of some complications, such as insulin dependent diabetes and hypothyroidism, were lower than previously recorded. Hence, it is to be hoped endocrine complications will be less common in the future, for patients who have started chelation therapy during the first years of life. Because of the improved survival of thalassaemic patients with insulin dependent diabetes, and the high incidence of multiple endocrine complications, it is important to carry out careful follow-up studies for the early detection of any other associated complications to facilitate correct treatment.