Discontinuation of Levothyroxine Therapy for Patients With Subclinical Hypothyroidism

This is a pilot, randomized, double-blind, placebo-controlled trial.

Methodology:

The investigators will conduct a double-blind, placebo-controlled clinical trial where eligible veterans diagnosed with SCH and on LT4 will be 1:1 randomized to either continue LT4 or change to placebo. The primary outcome is intervention feasibility (willingness to enter the trial, recruitment rate, and completion rate). Secondary outcomes are: 1) changes in QoL measures (Hypothyroid Symptom [HSS] and Tiredness scale scores of the Thyroid-Specific Patient-Related Outcome Measure [ThyPRO], EuroQoL 5-Dimension Self-Report Questionnaire) measured at baseline, 6-8 weeks and 6 months and 2) changes in lipids assessed at baseline and 6 months, and 3) incidence of adverse events (overt hypothyroidism, hyperthyroidism, atrial fibrillation, fractures, acute myocardial infarction, stroke, acute coronary syndrome, heart failure, mortality).

Inclusion criteria

• Veterans
• diagnosis of SCH

Exclusion criteria

• thyroid-stimulating hormone (TSH) > 10 milli-international units per liter (mlU/L) (at any point)
• Levothyroxine (LT4) dose more than 75 mcg daily
• use of antithyroid medications, amiodarone, tyrosine kinase inhibitors or lithium
• history of thyroidectomy or radioactive iodine therapy
• LT4 suppressive therapy for thyroid cancer, goiter, or inflammation
• pregnancy or plans for pregnancy in the next 6 months
• an unstable medical condition that would jeopardize safety or interfere with study participation
• severe hypothyroidism-related symptoms
• strong family history of hypothyroidism
• severe dyslipidemia
• hospitalization for major illness within the previous 4 weeks
• acute coronary artery syndrome, acute myocarditis, or pancarditis with the previous 12 months
• grade IV New York Heart Association heart failure
• receiving services from hospice
• lack of decision-making capacity
• terminal medical condition for which life expectancy would be less than 6 months
• not willing to stop LT4
• self-reported non-adherence to LT4 therapy
• abnormal TSH at time of screening for participation (assessed during Baseline Visit)