No benefit to treatment of subclinical hypothyroidism in adults 80 years and older

Reference

Mooijaart SP, Du Puy RS, Stott DJ, et al. Association between levothyroxine treatment and thyroid-related symptoms among adults aged 80 years and older with subclinical hypothyroidism. JAMA 2019;322(20):1977-1986.

Synopsis

Current recommendations do not support the treatment of subclinical hypothyroidism in adults. However, patients 80 years and older have been underrepresented in clinical trials and are more likely to report thyroid-related symptoms, such as constipation, mental slowness, fatigue, or depression. These investigators analyzed combined data from 2 separate clinical trials as a single study group of only patients 80 years or older with persistent subclinical hypothyroidism. Eligible participants randomly received (concealed allocation assignment) levothyroxine (initially 50 mcg daily, or 25 mcg daily for patients who weigh less than 50 kg or have a history of coronary heart disease) or matching placebo for 6 weeks to 8 weeks. The dose of levothyroxine was adjusted in 25-mcg increments based on thyrotropin levels measured after 6 to 8 weeks with a goal of attaining a thyrotropin level within the normal reference range (0.4 - 4.6 mIU/L). An identical schedule for adjusting the dose also occurred for the placebo group. Patients, investigators, and treating clinicians remained unaware of the results of thyrotropin measurements and treatment group assignment. Complete follow-up occurred for 92.4% of participants at 12 months. Using intention-to-treat analyses, no significant group difference occurred in the primary outcome of change from baseline to 12-month follow-up in a validated thyroid-related quality-of-life scoring tool. Similarly, no significant differences occurred in other prespecified secondary outcomes, including handgrip strength, activities of daily living, or executive cognitive function.