Endogenous subclinical hyperthyroidism: who, when and why to treat

Subclinical hyperthyroidism is defined as serum thyroid hormone levels within their respective reference ranges in the presence of low-undetectable serum thyrotropin-stimulating hormone levels. Subclinical hyperthyroidism is associated with important cardiovascular risk factors and negative effects on bone metabolism and structure. However, there are conflicting results on cardiovascular mortality and the risk of bone fractures. Treatment and management of subclinical hyperthyroidism is controversial. This article will address the necessity to treat this disorder in relation to the cause of hyperthyroidism, the patient's age, the degree of thyroid-stimulating hormone suppression and the presence of comorbidities