 Print page |
 Email page |
Thyroxine has beneficial actions in patients with subclinical hypothyroidism
The background of the study. Subjects with subclinical hypothyroidism (high serum thyrotropin [TSH] and normal thyroxine [T4] concentrations) may have some clinical, physiological, and biochemical findings of more severe hypothyroidism, but whether the findings improve during T4 therapy is controversial. This study was done to determine the effect of T4 in subjects with subclinical hypothyroidism.
How the study was done. The study was a double-blind crossover trial in which 100 subjects with subclinical hypothyroidism (82 women, 18 men; average age, 54 years) were given 100 µg of T4 and placebo daily in random order, each for 12 weeks. At base line and at the end of each treatment period, quality of life was assessed using the Short Form-36, a questionnaire that has physical- and mental-component scores, a Hypothyroidism Quality-of-Life questionnaire, and a Hypothyroid Symptom questionnaire. Weight, blood pressure, serum TSH, free T4 and lipids, and flow-mediated dilatation of the brachial artery, an indicator of vascular function, were measured at the same times.
The results of the study. The base-line results were similar in the T4-first and placebo-first groups; the average base-line serum TSH concentrations were 5.4 mU/ml (highest, 15.8) in the T4-first group and 5.3 mU/ml (highest, 13.9) in the placebo-first group. The average serum TSH concentration was lower and the serum T4 concentration was higher at the end of the T4 period than at the end of the placebo period.
There was slightly more improvement in the Hypothyroidism Quality-of-Life score and in some symptoms of hypothyroidism during T4 than during placebo administration. There were no differences in Short Form-36 scores, perceived health status, or treatment satisfaction.
Body weight and blood pressure were similar at the end of each period. The waist–hip ratio was lower after T4 administration (0.81 vs. 0.83), as were serum total and low-density lipoprotein (LDL) cholesterol concentrations, and the flow-mediated dilatation of the brachial artery was higher.
The conclusions of the study. In subjects with subclinical hypothyroidism, treatment with T4 for 12 weeks, as compared with placebo, results in improvement in some symptoms of hypothyroidism, lower serum total and LDL cholesterol concentrations, and improvement in endothelial function.
The original article. Razvi S, Ingoe L, Keeka G, Oates C, McMillan C, Weaver J. The beneficial effect of L-thyroxine on cardiovascular risk factors, endothelial function, and quality of life in subclinical hypothyroidism: randomized, crossover trial. J Clin Endocrinol Metab 2007;92:1715-23.
 Next Article: Thyroid incidentalomas are occasionally found in patients with head and neck cancer |
||
| Thyroid Digest Index | | | July 2007 Thyroid Digest |
