Considerations in the Diagnosis and Management of Thyroid Dysfunction in Older Adults

Background: Thyroid dysfunction is common in older adults and poses diagnostic and management challenges for clinicians. In this narrative review, we present published data focusing on special considerations in the diagnosis and management of hypothyroidism and hyperthyroidism in older adults. Methods: A comprehensive literature search of the PubMed and Ovid MEDLINE databases was conducted from January 2000 to December 2024 to identify pertinent articles in English for this narrative review. Results: Due to significant cardiovascular risk if untreated, both overt hypothyroidism and hyperthyroidism should be treated in older adults. Findings from observational studies do not support treating older adults with subclinical hypothyroidism with a thyrotropin (TSH) <7 mIU/L. However, observational data have demonstrated an increased risk of cardiovascular mortality and stroke in older adults with subclinical hypothyroidism with TSH 7.0-9.9 mIU/L and of coronary heart disease, cardiovascular mortality, and heart failure in those with TSH ≥10 mIU/L, suggesting levothyroxine treatment in these individuals should be considered. Data from clinical trials failed to show improvement with levothyroxine in hypothyroidism symptoms or fatigue in older adults with subclinical hypothyroidism compared with placebo. Over- and under-replacement with thyroid hormone is common and should be avoided, as population-based studies have shown associations with adverse cardiovascular and skeletal events. Subclinical hyperthyroidism with a TSH <0.1 mIU/L should be treated in older individuals as it has been associated with increased cardiovascular risk and bone density loss based on observational data. Randomized controlled trials have shown that long-term low-dose methimazole is a viable alternative to radioactive iodine in older adults with hyperthyroidism. Conclusions: A personalized approach should be undertaken in the diagnosis and management of thyroid dysfunction in older adults. Multiple factors should be considered, including physiological age-related changes in thyroid function, comorbidities, and polypharmacy. Care should be taken to maintain euthyroidism in order to avoid adverse events.