Screening for thyroid dysfunction in patients without symptoms: don’t routinely check that box

New guideline from the Canadian Task Force on Preventive Health Care

A new guideline from the Canadian Task Force on Preventive Health Care found no benefit of routine screening for thyroid dysfunction in adults without symptoms or risk factors. Based on the latest evidence, the Task Force guideline recommends against routine screening for thyroid dysfunction in non-pregnant adults and is published in CMAJ (Canadian Medical Association Journal).

Routine screening for thyroid dysfunction in people without symptoms or risk factors is commonly ordered, but practice varies by primary care practitioner. When done, blood tests are ordered – by checking the box on a requisition - to measure Thyroid Stimulating Hormone (TSH) levels which may indicate an underactive (hypothyroidism) or overactive thyroid gland (hyperthyroidism).

“Routinely screening for thyroid dysfunction in adults without any symptoms risks making patients out of otherwise healthy people,” explains Dr. Brett Thombs, Professor in the Department of Psychiatry at McGill University and Chair of the Canadian Task Force on Preventive Health Care.

“If you are a clinician who orders TSH tests as part of preventive health visits, we would like you to reconsider this practice. The evidence isn’t there to suggest a health benefit for this type of screening as a routine part of care,” says Dr. Richard Birtwhistle, Emeritus professor of Family Medicine and Public Health Sciences at Queen's University and Chair of the Task Force Thyroid Dysfunction working group.

“People with positive TSH tests are often prescribed medications that they take for the rest of their lives, that require medical monitoring, and that increase health care expenditures – without any detectable benefit to their health,” notes Dr. Thombs, who is also a Senior Investigator at the Lady Davis Institute of the Jewish General Hospital and a member of the working group.

Why did the Task Force make this recommendation?

The Task Force conducted a rigorous systematic review of the latest evidence. Although no screening trials were identified, 22 studies on the effectiveness of treatment for abnormal TSH findings in asymptomatic adults were included. The Task Force did not find evidence of benefits from screening and treatment in people without symptoms, but highlighted that screening requires patients to undergo testing.

Given the lack of benefit to patients, the need to take medication unnecessarily, and have regular medical visits and follow-up blood tests to check TSH levels, the Task Force strongly recommends against routine TSH screening in asymptomatic adults.

“Patients who are unusually tired, sensitive to cold or heat, experience hair loss, heartbeat irregularities, or unexpected weight loss or gain should consult a physician,” says Dr. Guylène Thériault, a family doctor, a specialist in public health and a member of the Task Force working group. “The recommendation outlined here applies to patients without any symptoms. It does not apply to people with symptoms I’ve described, or who have risk factors including surgery or radiation treatments in the neck.”

Clinical practice implications

• This recommendation may change practice for clinicians who routinely screen for thyroid function in asymptomatic patients.
   
• Clinicians should be aware of symptoms, signs, and conditions associated with thyroid dysfunction so that patients with these can be tested, particularly symptomatic postmenopausal women, given the higher prevalence of hypothyroidism in that population.
   

The College of Family Physicians of Canada, Nurse Practitioner Association of Canada and the Canadian Society of Endocrinology and Metabolism have endorsed the guideline.

For the full guideline, infographic overview and additional tools, click here. Listen to a related podcast on the guideline.

About the Canadian Task Force on Preventive Health Care

The Canadian Task Force on Preventive Health Care is an independent panel of health professionals who are experts in clinical preventive health care and guideline methodology. The Task Force’s mandate is to develop and disseminate evidence-based clinical practice guidelines for primary and preventive care.

“Recommendations on screening adults for asymptomatic thyroid dysfunction in primary care” is published November 18, 2019

Contact: Jason Clement, 514-398-5909 or Jason.clement [at] mcgill.ca