[Sub-clinical hypothyroidism, towards the end of a controversy?]

DEFINING THE PROBLEM: Sub-clinical hypothyroidism, defined as a moderate and isolated increase in TSH levels, is a common syndrome and is the first phase of a progressive disease. However its treatment remains controversial. Some anamnestic, clinical and biological (anti-thyroperoxidase antibodies) parameters contribute in identifying the patients most likely to progress towards overt hypothyroidism. WHAT CAN BE EXPECTED OF TREATMENT? Several clinical studies have described cardiovascular, neuromuscular and lipid disorders in these patients, but administration of levothyroxine has provided varying results and does not enable the distinction between a pharmacological-like intrinsic effect of the thyroid hormone and the true benefits imputable to the correction of TSH, in the absence of any large interventional study. More studies are required to better identify the patients who will benefit most from hormone replacement.