News

Evidence Inadequate to Support Routine Thyroid Screening

Author and Disclosure Information

Key clinical point: Current evidence is insufficient to assess the balance of benefits and harms of screening nonpregnant, asymptomatic adults for thyroid dysfunction.

Major finding: Only 3%-5% of adults in the United States have subclinical hypothyroidism, and only 0.7% have subclinical hyperthyroidism.

Data source: A comprehensive review of the current evidence and a compilation of recommendations regarding the benefits and harms of screening asymptomatic adults for thyroid dysfunction.

Disclosures: The USPSTF is an independent voluntary group of experts funded through congressional mandate by the Agency for Healthcare Research and Quality to make recommendations about the effectiveness of specific preventive care services for asymptomatic patients. Dr. LeFevre’s and his associates’ financial disclosures are available at www.uspreventiveservicestaskforce.org.


 

References

Current evidence is insufficient to assess the balance of benefits and harms of routinely screening nonpregnant, asymptomatic adults for thyroid dysfunction, according to a U.S. Preventive Services Task Force recommendation statement published online March 24 in the Annals of Internal Medicine.

In particular, there is not enough evidence to either support or refute the idea that such screening leads to clinically important benefits, such as reducing the incidence of cardiovascular disease and its related morbidity and mortality. Nor is there evidence that screening leads to early detection and treatment, which, in turn, improves quality of life or is beneficial for blood pressure, body mass index, bone mineral density, lipid levels, or cognitive function, said Dr. Michael L. LeFevre, chair of the task force and professor of family medicine at the University of Missouri–Columbia, and his associates.

On the other hand, the evidence concerning the harms of screening asymptomatic adults is also inadequate. It seems likely, but has not yet been proved, that screening large numbers of asymptomatic patients would result in frequent false-positive results and a “large degree” of overdiagnosis and overtreatment, given that only 3%-5% of adults have subclinical hypothyroidism and only 0.7% have subclinical hyperthyroidism. And the negative psychological effects of being labeled as chronically ill haven’t been well studied, either, the task force noted.

Regardless of this lack of evidence, it appears that many primary care providers already screen for thyroid dysfunction. Exact estimates are not available, but one brand of thyroid hormone is the most commonly prescribed drug in the country, and the number of filled prescriptions for levothyroxine rose 42% in a recent 5-year period. Given the high number of prescriptions and the low prevalence of overt thyroid dysfunction, “it is reasonable to conclude that many asymptomatic persons receive treatment. Clinicians seem to be treating more persons for thyroid dysfunction, at earlier times after initial diagnosis, and at TSH [thyroid-stimulating hormone] levels closer to normal,” Dr. LeFevre and his associates wrote (Ann. Intern. Med. 2015 March 24 [doi:10.7326/M15-0483]).

Continue for USPSTF recommendation statement >>

Pages

Recommended Reading

Can Vitamin D Supplements Help With Hypertension?
Clinician Reviews
Pediatric T2DM: A Growing Threat to US Health
Clinician Reviews
Oral Bisphosphonates Linked with Lower Risk of Endometrial Cancer
Clinician Reviews
Most Thyroid Nodules Have Favorable Prognosis
Clinician Reviews
FDA: Limit Testosterone Use to Men With Specific Medical Conditions
Clinician Reviews
Type 1 Diabetes Doubles Infection and Hospitalization Risk
Clinician Reviews
Type 2 Diabetes Lower in Familial Hypercholesterolemia
Clinician Reviews
CDC, AMA Launch Nationwide Prediabetes Awareness Initiative
Clinician Reviews
Achieving Diabetes Treatment Goals Rarely Influenced By Provider Beliefs
Clinician Reviews
ADA and EASD Recommend Improvements in Monitoring Insulin Pump Safety
Clinician Reviews