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In order to decide whether thyroxine treatment should or should not
be recommended, one requires several (and not just one!) placebo-controlled double-blind
randomized trials showing an improvement in the quality and extent of life. Such
conclusive evidence is not presently available, although less definitive studies suggests
that this may actually be so (24,29,31–33).
Anyway, in many occasions the physicians must reach a decision and give his advice in spite of the insufficient evidence available. Subclinical hypothyroidism is one of these cases. Many authors, including Fenzi et al. (2), Surks and Ocampo (8), Weetman (12), Danese et al (13), recommend thyroxine treatment, but others are more conservative . In his recent review Samuels (34) is ambivalent, recommending treatment in selected cases. The author is in full agreement with the advice to treat. The lipid profile is usually ameliorated. Tanis et al. (21) found that with treatment total serum cholesterol fell on average by only 0.4 mmol/l in hypercholesterolaemic patients with subclinical hypothyroidism. Even if moderate, this decrease is certainly welcome, and furthermore other lipid abnormalities such as the high density/low density ratio are also ameliorated. In addition, as stated before, there is a subjective feeling of improved well-being (28,29). More definite guidelines about treatment can be found at the end of this review. Treatment should be done cautiously, especially in elderly cardiac patients (34). The author advises a starting dose of 12.5 µg of thyroxine/day. The final dose required to keep TSH normal is usually lower than that for overt hypothyroidism (34). This is in agreement with the general rule that, the higher the pre-treatment TSH value, the greater the final dose of thyroxine required. |
