Should subclinical hypothyroidism in elderly patients be treated?

In contrast, studies of geriatric populations have not consistently shown associations between depression, memory loss or other symptoms and subclinical hypothyroidism. Despite this, some groups have recommended that all elderly patients with subclinical hypothyroidism and a TSH level greater than 10 mIU/L receive hormone replacement therapy (HRT) and that HRT be considered for older people with compatible symptoms and a TSH level between 5 and 10 mIU/L.1,2 To date, no randomized controlled trials have provided evidence to support these recommendations, and there is reason to suspect that they may be flawed. It is known that restriction in energy intake, with its associated reduction in metabolic rate, results in increased longevity in animal models of aging. Administration of thyroid hormone could theoretically accelerate the aging process by increasing metabolic rate. In addition, age-related hormone deficiencies (e.g., growth hormone) are not necessarily associated with poor outcomes. In fact, restoring hormone levels in older patients to those of younger patients may have adverse consequences.3