Screening for Thyroid Disease: A Recommendation from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Screening for Thyroid Disease: Recommendation Statement" and "Screening for Subclinical Thyroid Dysfunction in Nonpregnant Adults: A Summary of the Evidence for the U.S. Preventive Services Task Force." They are in the 20 January 2004 issue of Annals of Internal Medicine (volume 140, pages 125-127 and pages 128-141). The first report was written by the U.S. Preventive Services Task Force; the second report was written by M. Helfand.

What is the U.S. Preventive Services Task Force?

The U.S. Preventive Services Task Force (USPSTF) is a group of health experts that reviews published research and makes recommendations about preventive health care.

What is the problem and what is known about it so far?

The thyroid is a gland in the neck that produces hormones that help to regulate metabolism, the reactions that control how the body uses energy. Hyperthyroidism is a disease in which the thyroid makes too much thyroid hormone, speeding up many of the body's functions. Symptoms of hyperthyroidism include rapid heartbeat, feeling hot, anxiety, muscle weakness, frequent bowel movements, trouble sleeping, shakiness, light or missed menstrual periods, and weight loss. Hypothyroidism is a condition in which the thyroid makes too little thyroid hormone and body functions slow down. Symptoms of hypothyroidism include tiredness, feeling cold, constipation, hoarse voice, changes in hair and skin, heavy menstrual periods, and weight gain. Doctors diagnose thyroid disease by checking blood levels of thyroid hormones. Thyroid disease can usually be easily treated with drugs; radiation; or, occasionally, surgery. Thyroid disease is very common and not all patients develop symptoms, especially early in the course of the disease. Subclinical thyroid disease is a term that doctors use to describe people who have normal blood levels of thyroid hormones but abnormal levels of thyroid-stimulating hormone, which is made in the pituitary gland and regulates the thyroid gland. Doctors disagree about the need to treat subclinical thyroid disease. Some doctors think it helps patients to treat it, and others think it is best to wait until symptoms develop before starting treatment

How did the USPSTF develop these recommendations?

The USPSTF reviewed published research to measure the benefits and harms of testing for thyroid disease in people with no symptoms of thyroid disease.

What did the USPSTF find?

The USPSTF found no convincing studies to show that patients with subclinical thyroid disease do better if they begin treatment for thyroid disease before symptoms develop than if they wait for symptoms to develop before starting treatment. Overtreatment of thyroid disease with thyroid hormone can lead to complications such as nervousness and abnormal heart rhythm.

What does the USPSTF suggest that patients and doctors do?

Patients and doctors should consider testing for thyroid disease if patients have any of the symptoms that occur in hypothyroidism or hyperthyroidism. However, before considering thyroid tests for patients with no thyroid symptoms, doctors and patients should be aware that it is uncertain whether patients benefit from finding and treating thyroid disease before symptoms develop.

What are the cautions related to these recommendations?

The recommendations may change as new studies become available. Some other professional societies do recommend screening for thyroid disease.