Levothyroxine Shows No Benefit in Older Adults with Subclinical Hypothyroidism

By Amy Orciari Herman

Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

Levothyroxine therapy seems to offer no benefit to older adults with subclinical hypothyroidism, according to a New England Journal of Medicine study presented at the Endocrine Society's ENDO 2017 meeting.

The study included nearly 740 adults aged 65 or older who had thyroid-stimulating hormone (TSH) levels ranging from 4.60 to 19.99 mIU/L plus free thyroxine in the reference range. Participants were randomized to receive daily levothyroxine or placebo. Levothyroxine was started at 50 µg/day (or 25 µg/day for those who weighed under 50 kg or had coronary heart disease), with dose adjustment targeting a TSH level of 0.40–4.59 mIU.

The two primary outcomes — changes in a hypothyroidism symptom score and a tiredness score at 12 months — did not differ significantly between the groups. Secondary outcomes, including cognitive function and performance in activities of daily living, also did not differ.