Another Look at Treatment of Subclinical Hypothyroidism

In a recent randomized trial that involved older patients (age, ≥65) with subclinical hypothyroidism, 1 year of L-thyroxine therapy, compared with placebo, did not improve fatigue or quality-of-life scores (NEJM JW Gen Med May 15 2017 and N Engl J Med 2017; 376:2534). However, in that study, outcomes were reported only for the overall study population, which raises the following question: Could L-thyroxine therapy have been beneficial in the most-symptomatic patients? To find out, researchers conducted this secondary analysis. At baseline, all patients had elevated serum thyroid-stimulating hormone (TSH) levels (4.60–19.9 mIU/L) but normal free thyroxine levels. In the treatment group, L-thyroxine therapy was titrated to achieve normal TSH …