Indications for Dose Adjustment of Thyroid Hormones in Older Patients

Thyroid dysfunction is common in older people (persons aged 65 and above). A meta-analysis of data from European countries revealed a 4.1% prevalence of undiagnosed subclinical hypothyroidism. It was found in a primary care study from the United Kingdom that approximately 10 percent of people over age 70 were under treatment for hypothyroidism.

This narrative review is based on findings in relevant publications retrieved by a PubMed search and on the guidelines of the European Thyroid Association and the American Thyroid Association.

Overtreatment with levothyroxine increases the risk of cardiovascular, cognitive, and skeletal complications (hazard ratio 1.37-2.02). Randomized controlled trials have not shown that treatment with levothyroxine (T4) improves presumed symptoms of hypothyroidism, body weight, or fatigue. In patients who are now taking levothyroxine, lowering the dose or stopping the drug should be considered; in older patients, the target range for thyroid-stimulating hormone (TSH) should be 4-10 mU/L. After levothyroxine is stopped, some patients remain euthyroid; in the absence of an indication, gradual tapering may be considered. Levothyroxine should not be given over the long term to patients with thyroid nodules. Subclinical hyperthyroidism in older people is associated with clinically relevant risks, particularly atrial fibrillation and bone fractures, and should therefore be treated. Its most common cause, however, is levothyroxine treatment that is either not indicated or improperly dosed.

While overt hypothyroidism and hyperthyroidism must be treated at any age, the need to treat subclinical hypothyroidism should be individually assessed; subclinical hyperthyroidism, by contrast, generally warrants treatment given its associated risks. In view of the risks of inadequately treated hyperthyroidism and excessively dosed levothyroxine, physicians should regularly review the indication for treatment, the dosage, and the possibility of lowering the dose or discontinuing the drug.