Practice: The authors state the following.
1. Primary care office-based screening with a sensitive TSH test in women older than 50 years of age may be indicated.
2. A free thyroxine test should be done in women older than 50 years of age when the TSH level is undetectable or is 10 mU/L or greater.
3. Screening in women younger than 50 years of age and in men is not warranted because the prevalence of unsuspected overt thyroid dysfunction is low.
4. Patients who are found to have relatively specific symptoms and signs (such as goiter, nodule, eye findings of Graves disease or tremor) should be referred to an endocrinologist for consideration of treatment, but the management of patients with none of these findings is not clear.
5. The available evidence is not sufficient to recommend for or against treatment for subclinical hypothyroidism.
Research: The authors make the following suggestions for future research.
1. Large randomised trials are needed to determine the likelihood that treatment will improve quality of life in otherwise healthy patients who have mildly elevated TSH levels.
2. Larger, well-designed randomised trials are needed to determine whether treatment would be effective in office based screening of otherwise healthy primary care patients.
3. Future prospective, concurrent comparison studies should examine the effects of screening on health outcomes. These studies should be large enough to determine the likelihood that specific subgroups of patients will benefit from treatment in relation to their age, sex, clinical findings, quality of life, and TSH level.