Natural Course of Subclinical Hypothyroidism

Abstract

Objectives of this retrospective study were to evaluate the natural course of subclinical hypothyroidism (SH) and to estimate possible predictable factors of overt hypothyroidism. Population of the study was selected from the patients with spontaneously elevated thyrotropin (TSH) and normal free thyroxin (fT4) levels. Overall 87 patients (12 male, 75 female) with SH without any therapy with thyroid hormones or iodide drugs or without previous thyroid surgery, thyrostatic therapy, or radioactive iodine therapy were included in the analysis. Results: the main risk factors of overt hypothyroidism in this population were positive thyroid antibodies (odds ratio = 3.99) and high initial level of TSH (>8 mU/l) (odds ratio = 4.77). Patient’s age, gender or duration of SH did not affect significantly the risk of overt hypothyroidism. Conclusions: rational substitutive therapy with thyroid hormones was not discussed in this study, however the data suggest that positive thyroid antibodies and relatively high TSH level may be useful to decide upon such therapy in individuals with SH. Key words: hypothyroidism, Hashimotos, thyroiditis, thyrotropin.