Management of Subclinical Hypothyroidism: The 2023 Korean Thyroid Association Guidelines

Subclinical hypothyroidism (SCH) is characterized by elevated serum thyroid-stimulating hormone (TSH) levels and normal free thyroxine levels. The Korean Thyroid Association recently issued guidelines for managing SCH. Based on the Korea National Health and Nutrition Examination Survey (2013-2015), a serum TSH level of 6.8 mIU/L is the reference value for SCH. SCH is classified as mild (TSH 6.8-10.0 mIU/L) or severe (TSH > 10.0 mIU/L), and patients are categorized as adult (age < 70 years) or elderly (age ≥ 70 years). Levothyroxine treatment (LT4-Tx) is not recommended for mild or even severe SCH in elderly patients. Immediate LT4-Tx can be given to adults in most cases, but not to women who are pregnant, patients with progressive disease, or patients with underlying coronary artery disease, heart failure, or dyslipidemia.