Thyroid dysfunction in chronically transfused adults with β-thalassemia major

Abstract

Aim: This study aims to determine the prevalence and severity of thyroid dysfunction in adult β-thalassemia major (BTM) patients and to investigate its relationship with the frequency of transfusions, serum ferritin levels, and adequacy of oral chelation therapy. Material and Methods: This study included 62 adult patients diagnosed BTM and had been receiving regular blood transfusions for at least 1 year. Iron load was defined as the serum ferritin level. Thyroid dysfunction was categorized as primary hypothyroidism (thyroid-stimulating hormone (TSH)>5.6 mU/L and serum-free thyroxine (FT4)<0.61 ng/dL), subclinical hypothyroidism (Normal FT4 with TSH>5.6 mU/L) or secondary hypothyroidism (FT4<0.61 ng/dL with low or normal TSH). Patients’ data was presented retrospectively. Results: The prevalence of hypothyroidism was 22.6%, and the prevalence of primary hypothyroidism was 14.6%. Mean ferritin levels were determined as 5283.64±2023.95 ug/L, and 1868.67±955.98 ug/L respectively for patients with hypothyroidism, and euthyroidism; and a significant difference was determined between the two groups (p=0.001). Thyroid dysfunction was encountered more frequently in patients receiving four units of blood transfusion per month, and high-dose chelation therapy (both p=0.001). Severity of thyroid dysfunction was determined to have a statistically significant relationship with increased serum TSH, and decreased serum FT4 levels. Conclusion: This study determined primary hypothyroidism as the most common subtype of thyroid dysfunction. A significant relationship was found between thyroid dysfunction and serum ferritin levels. In view of these data; reducing the incidence of thyroid dysfunction appears to be possible through successful management of iron chelation therapy in patients receiving regular blood transfusions.