Subclinical hypothyroidism does not cause symptoms but can lead to long-term risks of conditions like heart disease. Stott and colleagues tested the effectiveness of levothyroxine for hypothyroidism and found it had no benefit in older patients.
Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone. Thyroid hormone is important in many aspects of body function, and not having enough can lead to fatigue, weight gain, and depression, among other symptoms. Between 8% and 18% of people over 65 years of age suffer from subclinical hypothyroidism. Individuals with this condition don’t show any symptoms, but are at increased risk of other ill health effects down the line, including heart disease.
Levothyroxine is a manmade alternative to thyroid hormone that can be used as a hypothyroidism treatment. However, its effectiveness in individuals with subclinical hypothyroidism is not well documented. Stott and colleagues published a paper in the New England Journal of Medicine in which they tested levothyroxine as a treatment for subclinical hypothyroidism in older adults. Their sample consisted of 737 adults with subclinical hypothyroidism and an average age of 74.4 years. Patients received either 50 nanograms of levothyroxine or placebo, but doses were adjusted for individuals with known heart disease. The study was double-blind, so that neither patients nor doctors knew which treatment the patient was receiving. The researchers followed patients for 12 months. They used the Thyroid-Related Quality-of-Life Patient-Reported Outcome questionnaire to assess quality of life, as well as various measures of physical health as well as cognitive and motor function.
Patients who received treatment had significantly lower levels of thyrotropin, and higher levels of thyroid hormone, than patients who received placebo. Thyrotropin regulates the production of thyroid hormone and is high in patients with hypothyroidism. However, there were no differences in symptoms, quality of life scores, or health status between groups at the end of the study. Levothyroxine appears to provide no benefit to older patients.
Larger studies covering longer periods of time are needed to assess the long-term effects of treatment on patients with subclinical hypothyroidism. Patients may also need higher doses of levothyroxine to experience any benefits, and the effects may be greater in patients with a more severe starting condition.
Written By: C. I. Villamil