What is the significance of elevated Thyroid-Stimulating Hormone (TSH) levels in a patient over 90 years old?

From the Guidelines

Elevated TSH levels in patients over 90 years old should not be treated with thyroid hormone replacement unless they are symptomatic, due to the potential risks of overtreatment and the lack of evidence showing a mortality benefit in this age group. The significance of elevated Thyroid-Stimulating Hormone (TSH) levels in a patient over 90 years old is a topic of debate, with some studies suggesting that treatment may not be necessary unless symptoms are present 1. Some key points to consider include:

• The prevalence of thyroid dysfunction increases with age, but the majority of cases are subclinical and may not require treatment 1.
• The use of thyroid hormone therapy is common in older adults, with data from the CHS showing a steady increase in the overall percentage of older adults receiving thyroid hormone therapy 1.
• However, the median TSH level at initiation of thyroid hormone therapy has decreased over time, suggesting that some patients may be overtreated 1.
• The goal TSH for someone over 90 years old should be more liberal, typically aiming for 4-6 mIU/L rather than the stricter targets used for younger adults, but only if symptoms are present.
• Treatment with levothyroxine should be started at a low dose and gradually increased, with regular monitoring of TSH levels to avoid overtreatment and minimize the risk of cardiovascular complications.
• It is essential to weigh the potential benefits of treatment against the risks, particularly in older adults with multiple comorbidities, and to prioritize treatment only for those who are symptomatic.

From the Research

Significance of Elevated TSH Levels in Patients Over 90 Years Old

• Elevated Thyroid-Stimulating Hormone (TSH) levels in patients over 90 years old can be an indication of hypothyroidism, a common disorder characterized by inadequate thyroid hormone secretion 2, 3.
• The diagnosis of hypothyroidism in elderly patients can be challenging due to the similarity between thyroid-associated symptoms and symptoms of the aging process 3, 4.
• TSH levels increase with age, and between 30% and 60% of high TSH levels are not confirmed on a second blood test 2.
• Subclinical hypothyroidism, characterized by high blood TSH levels and normal free T4 levels, is rarely symptomatic and has a risk of progression to overt hypothyroidism of about 3% to 4% per year overall 2, 5.

Treatment Considerations

• Treatment guidelines for hypothyroidism are mainly based on physiological and pharmacological considerations, and generally recommend levothyroxine therapy 2, 3.
• However, the treatment of subclinical hypothyroidism is controversial, and there is no evidence that levothyroxine therapy has any tangible benefit in patients with subclinical hypothyroidism 2, 5.
• In elderly patients, the treatment of hypothyroidism requires caution, frequent cardiovascular monitoring, and individualized medicine 4, 6.
• The TSH goal is age-dependent, with a 97.5 percentile (upper limit of normal) of 3.6 mIU/L for patients under age 40, and 7.5 mIU/L for patients over age 80 5.

Management of Elevated TSH Levels

• Watchful waiting is an alternative to routine levothyroxine prescription in case of TSH elevation, especially in patients with slightly elevated TSH levels 2.
• The diagnosis of hypothyroidism should be confirmed by repeat thyroid function tests, and treatment should only be considered if the TSH exceeds 7.0-10 mIU/L 5.
• In patients with subclinical hypothyroidism, close monitoring of thyroid function could be the best option, especially in those with a high risk of progression to overt disease 3, 6.