Patients with subclinical hypothyroidism do not benefit from levothyroxine regardless of their level of symptoms, a major European trial shows.

Older patients with a high symptom burden showed no apparent improvement with levothyroxine compared to placebo according to a posthoc analysis of the randomised, placebo-controlled trial TRUST (Thyroid Hormone Replacement for Untreated Older Adults with Subclinical Hypothyroidism Trial).

The original study involving 737 patients people over the age of 65 who had persisting subclinical hypothyroidism previously showed there was no overall clinical benefit of levothyroxine in terms of change in the Hypothyroid Symptoms score and Tiredness score on a thyroid-related quality-of-life questionnaire at one year.

And now a newly published analysis of a subgroup of 132 trial participants who had Hypothyroid Symptoms scores greater than 30 and 133 with Tiredness scores greater than 40 has found no difference in improvements between levothyroxine and placebo groups.

The average TSH level was about 6.3 mIU/L in the high-symptom-burden group. Patients were assigned to receive levothyroxine at a starting dose of 50 μg daily, with dose adjustment according to the thyrotropin level.

Over one year the patients treated with levothyroxine showed a 12.3-point improvement from baseline in hypothyroid symptom scores, compared to a 10.4-point improvement in the placebo group.

The difference was not significant, and there was likewise no difference in tiredness scores or measures of quality of life and hand grip strength between levothyroxine and placebo.

“In the absence of another randomised clinical trial specifically designed for persons with SCH and high symptom burden, these results do not support routine L-thyroxine therapy among older adults with SCH, including those with greater hypothyroid symptom burden and tiredness,” the study investigators concluded.

The findings are published in Annals of Internal Medicine.