Subclinical hypothyroidism in older individuals

Subclinical hypothyroidism, which is defined as a thyroid-stimulating hormone concentration higher than the reference range (generally 4middot5 mIU/L or higher) with normal free thyroxine concentrations, is frequently found in older individuals. International guidelines differ in recommendations for management of subclinical hypothyroidism in older individuals. We assessed published data during the past decade on the clinical significance and treatment of subclinical hypothyroidism in individuals aged 65 years and older. Meta-analyses, randomised clinical trials, and cohort studies are discussed in this narrative Review. Studies showed no significantly increased incidence in adverse cardiovascular, musculoskeletal, or cognitive outcomes in individuals aged 65 years or older when serum thyroid stimulating hormone concentration was 4middot5-7middot0 mIU/L versus a euthyroid group. Moreover, in older individuals with subclinical hypothyroidism, symptoms of hypothyroidism and cardiac and bone parameters did not improve after levothyroxine treatment. These data suggest that treatment with levothyroxine should be considered for individuals aged 65 years or older with subclinical hypothyroidism when thyroid-stimulating hormone concentration is persistently 7 mIU/L or higher and to not initiate treatment with thyroid-stimulating hormone concentrations of less than 7 mIU/L. Levothyroxine doses should be personalised according to age, comorbidities, and life expectancy.

Automated summary

Subclinical hypothyroidism is common in older individuals and international guidelines differ in its management recommendations. Studies have shown that there is no significant increase in adverse cardiovascular, musculoskeletal, or cognitive outcomes in individuals aged 65 years and older with thyroid-stimulating hormone concentrations ranging from 4.5-7.0 mIU/L compared to those with normal thyroid function. Additionally, levothyroxine treatment did not improve symptoms or cardiac and bone parameters in older individuals with subclinical hypothyroidism. Thus, levothyroxine treatment should be considered for older individuals with subclinical hypothyroidism when thyroid-stimulating hormone concentration is persistently 7 mIU/L or higher.