Context: Although the negative impact of subclinical hypothyroidism (sHT) in terms of cardiovascular risk in
young adults is mostly acknowledged it remains to be established in the elderly, especially in the oldest old.
Evidence Acquisition: We searched Medline for reports published with the following search words: hypothyroidism, sHT,
ageing, elderly, L-thyroxin, thyroid, guidelines, treatment, quality of life, cardiovascular risk, heart failure (HF), ischemic
heart disease (IHD), endothelial dysfunction. The search was restricted to reports published in English since 1980, but
some reports published before 1980 were also incorporated. We supplemented the search with records from personal files
and references of relevant articles and textbooks. Parameters analyzed included epidemiology of sHT and thyroid failure
the effect of thyroid hormone on ageing process and cardiovascular function as well as the potential benefits of L-thyroxin
therapy on quality of life, HF progression and events.
Evidence Synthesis: TSH levels increase with age, even in older patients without thyroid disease, in whom higher TSH
value might favor longevity; better quality of life and lower IHD mortality in the oldest old population has been reported
yet. However, at odds with the relationship between sHT and IHD risk and mortality, which shows a clear age dependent
feature, vanishing in the last decades of life, the detrimental effect of sHT on HF progression and events remains evident
also in older patients, although no data are available in the oldest old population.
Conclusions: The lack of specific randomized trials enrolling either old or very old subjects, aimed at evaluate the efficacy
of hormonal replacement on overall survival and cardiovascular risk reduction along with the negative effects of possible
over-treatment, makes the decision to treat older people a still unresolved clinical challenge. Moreover, the possibility that
restoring euthyroidism may be harmful in the elderly should be always taken into account.