This statement summarizes the prese...

This statement summarizes the present U.S. Preventive Services Task Force (USPSTF) recommendation in succession screening for thyroid disease and the supporting scientific evidence, and updates the 1996 recommendations contained in the Guide to Clinical Preventive Services, next to the first Edition: Periodic Updates. (1) Explanations of the ratings and of the impregnability of overall evidence are given in Tables 1 and 2 The unbroken information on which this statement is based, including evidence tables and relations is available in the Systematic Evidence Review "Screening for Thyroid Disease," (2) available between the sides of the USPSTF Web site (http://www.preventiveservices.ahrq.gov) and between the sides of the National Guideline Clearinghouse (http://www.guideline.gov). The recommendation statement and summary article also are available between the walls of the USPSTF Web site and in print end the AHRQ Publications Clearinghouse (telephone: 800-3589295; e-mail: ahrqpubs@ahrq.gov).

This article first appeared in Ann Intern M 2004;140:125-7

Summary of Recommendation

* The USPSTF deduces that the evidence is insufficient to approve for or against routine screening for thyroid disease in adults. I recommendation.

The USPSTF fix fair evidence that the thyroid-stimulating hormone (TSH) criterion can detect subclinical thyroid disease in someones without symptoms of thyroid dysfunction, moreover poor evidence that treatment improves clinically important consequences in adults with screen-detected thyroid disease. Although the yield of screening is greater in certain high-risk collections (e.g., postpartum women, persons with Down syndrome and the elderly) the USPSTF raise poor evidence that screening in these arranges leads to clinically important benefits. There is the potential for harm caused through false-positive screening tests; however, the magnitude of harm is not known. There is beneficial evidence that overtreatment with levothyroxine appears in a substantial proportion of patients, yet the long-term harmful effects of overtreatment are not known. As a arise the USPSTF could not determine the balance of benefits and harms of screening asymptomatic adults for thyroid disease.

Clinical Considerations

* Subclinical thyroid dysfunction is defined as an abnormal biochemical measurement of thyroid hormones without any specific clinical signs or symptoms of thyroid disease and no history of thyroid dysfunction or therapy. This includes ones who have mildly elevated TSH on a levels and normal thyroxine ([T.sub.4]) and triiodothyronine ([Tsub3]) of the same heights (subclinical hypothyroidism), or low TSH plains and normal [T.sub.4] and [Tsub3] on a levels (subclinical hyperthyroidism). Individuals with symptoms of thyroid dysfunction, or those with a history of thyroid disease or treatment, are exclud from this definition and are not the enslave of these recommendations.

* When used to confirm suspected thyroid disease in patients referr to a specialty endocrine clinic, TSH has a high sensitivity (98 percent) and specificity (92 percent) When used for screening primary care populations, the positive predictive value of TSH in detecting thyroid disease is low; further, the interpretation of a positive proof result often is complicated by way of an underlying illness or from frailty of the patient. In general, values for serum TSH below 01 mU for L are considered low, and values above 65 mU for L are considered elevated.

* Clinicians should be aware of wily signs of thyroid dysfunction, particularly among those at high risk. bodily forms at higher risk for thyroid dysfunction include the somewhat old postpartum women, those with high flushs of radiation exposure (greater than 20 mGy) and those with Down syndrome Evaluating for symptoms of hypothyroidism is difficult in patients with Down syndrome because any symptoms and signs (e.g., dull speech, thick tongue, slow mentation) are typical findings in the two conditions.

* Subclinical hyperthyroidism has been associated with atrial fibrillation, dementia and, les clearly, osteoporosis. However, progression from subclinical to clinical disease in patients without a history of thyroid disease is not clearly established.

* Subclinical hypothyroidism is associated with poor obstetric issues and poor cognitive development in children. Evidence for dyslipidemia, atherosclerosis, and decreased quality of life in adults with subclinical hypothyroidism in the general population is inconsistent and les convincing.

Discussion

Subclinical thyroid disease is frequently more common than overt disease in primary care populations. Up to 5 percent of women and 3 percent of men have subclinical hypothyroidism (3); prevalence increases with age and is greater in whites than in blacks. (34) Untreated hypothyroidism can lead to fatigue, weight gain, mental slowing, heart failure, and elevated lipid evens Subclinical hyperthyroidism is less universal occurring in 1 percent of men older than age 60 and 15 percent of women older than age 60 (5) Untreated hyperthyroidism can lead to atrial fibrillation, congestive heart failure, osteoporosis, and neuropsychiatric problems