Frequency of hypothyroidism in patients of beta-thalassaemia.

Objective: To determine the frequency of hypothyroidism in patients suffering from homozygous beta-thalassaemia.

Methods: This descriptive study included 70 diagnosed thalassaemia major patients aged 5-14 years. Demographic data as well as history of blood transfusion and chelation therapy was collected. Random blood samples were drawn and thyroid profile (serum thyroxine [T4], triiodothyronine [T3] and thyroid stimulating hormone concentrations [TSH]) was done by enzyme-linked immunosorbent assay (ELISA). Primary hypothyroidism was defined by a TSH level > 4 microIU/ml. Results were analysed by descriptive statistical methods.

Results: Primary hypothyroidism was seen in 18 (25.7%) patients. Of these, 17 had normal T4 levels with elevated TSH levels consistent with a diagnosis of compensated primary hypothyroidism whereas only one patient showed a decreased T4 level with elevated TSH (uncompensated primary hypothyroidism). Mean age of hypothyroid patients was 9.2 +/- 2.6 years. Frequency of hypothyroidism was associated with increased serum ferritin levels.

Conclusion: Primary hypothyroidism occurs in a significant proportion of thalassaemia major patients in the absence of obvious clinical signs of hypothyroidism. Regular follow-up for early detection and timely treatment of such complications could improve the quality of life of these patients.