Level III Services: Preventive services that clinicians and care systems could provide to patients, but only after careful consideration of the costs and benefits. Providing these services is left to the judgment of individual care systems, clinicians and their patients.
|The USPSTF recommendations are fully endorsed by the ICSI Preventive Services work group.
||Grade of Recommendation and Level of Certainty as Evaluated by USPSTF|
||Grade of Recommendation:
Level of Certainty:
A potential benefit of treating subclinical hypothyroidism is to prevent the spontaneous development of overt hypothyroidism, but this potential benefit has not been studied in clinical trials. If the potential benefit suggested by data from a longitudinal survey is real, the USPSTF estimates that in a reference population of 1,000 women screened, three cases of overt hypothyroidism would be prevented in five years, but 40 people would have taken medication for five years without a clear benefit.
The potential harms of screening and treatment are principally the adverse effects of antithyroid drugs, radioiodine, thyroid surgery, and thyroid replacement therapy if detection and early treatment for subclinical disease are unnecessary. People with a false-positive TSH test result (more common in those with a severe underlying illness or those who are frail or elderly) may be subjected to unnecessary treatment or may have adverse psychological consequences (e.g., labeling). The USPSTF reviewed only the adverse effects of LT4 replacement therapy for mild thyroid failure and potential adverse effects of long-term treatment. These adverse effects were not carefully assessed in the randomized trials. Although some studies have suggested that women with a low TSH as a result of taking thyroid hormone replacement are at higher risk for developing osteoporosis, a recent systematic review did not support this finding. Overtreatment with LT4 is a potential risk: about one in four patients receiving LT4 is maintained unintentionally on doses sufficient to fully suppress TSH. Data from the Framingham Study suggest that one excess case of atrial fibrillation might occur for every 114 patients treated with LT4 sufficient to suppress TSH.
The goal of screening for thyroid disease is to identify and treat patients at risk for the health consequences of thyroid dysfunction before they become clinically apparent. The USPSTF examined the evidence for screening people who have no known history of thyroid disease and no or few signs or symptoms. The USPSTF found no controlled studies that examined whether routine screening for thyroid disease in the primary care setting leads to improved symptoms or other health outcomes.”