Should Older Patients with Subclinical Hypothyroidism be Treated with Thyroid Replacement?

With increasing age, many patients develop subclinical hypothyroidism. Subclinical hypothyroidism is defined by the presence of elevated thyroid stimulating hormone (TSH) but normal free T4 levels. Some patients with subclinical hypothyroidism also have symptoms that are not uncommon with increasing age such as constipation, tiredness, mental slowness, and fatigue.

Prior studies have found no association between treating patients with subclinical hypothyroidism with thyroid replacement therapy and resolution of symptoms. However, very old individuals (older than 80 years) are often not included in the studies.

To examine if treatment of subclinical hypothyroidism with thyroid replacement therapy results in resolution of such symptoms, Moojiraat et al. combined data from two randomized controlled trials. Combining data from two trials results in increased number of patients above 80 (and hence power of the study to detect a difference).

Contrary to expectations, but consistent with previous findings, thyroid replacement therapy does not result in resolution of symptoms in patients with subclinical hypothyroidism. Instead, there may be some increase in adverse events.