Context

Subclinical hypothyroidism (SCH), defined as an elevated serum thyroid-stimulating hormone (TSH) with normal circulating free thyroid hormones, is a common and frequently asymptomatic condition. SCH becomes increasingly prevalent with advancing age,1 and current guidelines recommend no treatment for older patients with serum TSH concentrations between the upper limit of the reference range and 10 mU/L.2 However, as numerous large epidemiological studies show an excess of cardiovascular events and/or increased mortality in patients with SCH,3 there are important questions about whether long-term levothyroxine treatment could either ameliorate vascular risk in this population or improve symptoms of hypothyroidism.