Should We Treat Subclinical Hypothyroidism?

Indications for treatment in subclinical hypothyroidism are not
established, but general guidelines can be offered. Greater magnitude
and duration of TSH elevation and higher titers of antithyroid
antibodies increase the probability that the condition will progress to
overt hypothyroidism and, therefore, increase the potential benefit of
treatment with levothyroxine. The presence of symptoms that might be
related to mild hypothyroidism also increases the potential benefit of
treatment. Risk of harm to the patient, against which this potential
benefit must be balanced, is quite small, since the use of the
sensitive TSH assay provides assurance that we are not raising the
blood thyroid hormone levels too much as long as TSH levels do not fall
below the normal range. In patients with coronary artery disease and
minimal elevations of TSH, however, it may be advisable to follow the
TSH level rather than subject the patient to the small risk of
levothyroxine therapy.

In short, it seems reasonable to treat patients who have a TSH level
that is consistently elevated above 10 ľU per mL (10 mU per L),
especially if titers of antithyroid antibodies are increased. Also,
patients who complain of fatigue, dry skin, constipation, muscle cramps
or other common symptoms of hypothyroidism may possibly benefit from
treatment even if their TSH level is elevated only into the 5 to 10 ľU
per mL (5 to 10 mU per L) range.