Screening and Treatment of Subclinical Hypothyroidism or Hyperthyroidism. Executive Summary. Effective Health Care Program. Cooperative Effectiveness Review Number 24.

摘要

Mildly elevated or decreased serum thyroid stimulating hormone (TSH, also called thyrotropin) levels are the most common abnormalities related to thyroid function. Subclinical thyroid dysfunction, defined as an abnormal TSH with normal levels of serum thyroid hormones (T3 and T4), affects 5 percent of women and 3 percent of men. Subclinical hypothyroidism is defined as a high TSH and normal T3/T4, and subclinical hyperthyroidism as having a low or undetectable TSH and normal T3/T4. Subclinical thyroid dysfunction has been shown to be a risk factor for the later development of overt thyroid disease. In addition, a high TSH level may be a risk factor for coronary events, elevated cholesterol levels, and increased rates of congestive heart failure, while a low TSH level is a risk factor for atrial fibrillation and osteoporosis. Therefore, it has been proposed that screening for and treating subclinical thyroid dysfunction might lead to a decrease in the morbidity associated with overt thyroid disease, heart disease, and possibly osteoporosis. To date, evidence-based reviews have recommended against routine screening and treatment of subclinical thyroid dysfunction, primarily based on the lack of evidence that treating subclinical thyroid dysfunction improves patient-centered outcomes.