Lack of benefit of thyroxine in patients
with mild subclinical hypothyroidism
(July 2002)
The background of
the study. Subclinical hypothyroidism (high serum thyrotropin
[TSH], normal serum thyroxine [T4]) is common. Whether patients
with the disorder have symptoms and whether the symptoms improve
with T4 therapy are controversial. In this study T4 therapy was
evaluated in carefully selected patients with subclinical hypothyroidism.
How the study was done. The study
subjects were 45 women (mean age, 49 years) who had symptoms suggestive
of hypothyroidism and who had serum TSH concentrations between 5
and 10 mU/L and normal serum free T4 concentrations. The women were
randomly assigned to receive 0.05 mg T4 or placebo daily for six
months. Health questionnaires were administered, and symptoms of
hypothyroidism and thyroid function and serum lipids were measured
before and after T4 therapy for three and six months.
The results of the study. The base-line
characteristics, including all questionnaire scores, the hypothyroid
symptom score, and biochemical values, of the women in the two groups
were similar. Twenty women in the T4 therapy group and 15 women
in the placebo group completed the study.
At six months, the mean serum TSH concentration decreased by 4.6
mU/L in the T4 therapy group and by 1.7 mU/L in the placebo group.
The health questionnaire scores did not change significantly in
either group, nor did the proportions of women in whom the scores
improved, did not change, or worsened. The hypothyroid symptom score
decreased to a similar extent in both groups. There were no changes
in body-mass index or serum lipid concentrations in either group.
The conclusions of the study. T4
therapy for six months has no benefit in women with mild subclinical
hypothyroidism.
The original article. Kong WM, Sheikh
MH, Lumb PJ, Freedman DB, Crook M, Doré CJ, Finer N. A 6-month
randomized trial of thyroxine treatment in women with mild subclinical
hypothyroidism. Am J Med 2002;112:348-54.
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