Correlation of cognitive test scores and adequacy of treatment in adolescents with congenital hypothyroidism. New England Congenital Hypothyroidism Collaborative.
OBJECTIVE
To measure the frequency of noncompliance and its possible effect on school achievement test and cognitive test scores in our older patients with congenital hypothyroidism.


METHODS
Fifty patients born from 1976 through 1978 were studied at home when they were 14 years of age. Each patient was given a battery of psychometric and school achievement tests, and blood for hormonal assays was drawn without forewarning from 36 of the patients on the day of examination. Efforts were made to improve control after the second year. During the third summer the tests were repeated in 25 of the 29 patients who had been tested at the age of 14; thyrotropin and thyroxine concentrations were measured in 23 of these 25 patients.


RESULTS
At the age of 14 years 16 of the 36 children had poorly controlled hypothyroidism, as defined by thyrotropin values greater than 15 mU/L. Of these 16 patients, 13 also had thyroxine concentrations of less than 85 nmol/L (6.6 micrograms/dl). A second examination at 15 or 16 years of age disclosed significant improvements in hormonal concentrations without changes in thyroxine dosage. Poor control was demonstrated on at least one occasion in 74% of 27 children older than 12 years of age who had 3 to 8 thyrotropin measurements during a period of 9 months. Cognitive test results in the patients did not differ from those in control subjects or from previous test results in the same children. The improved hormonal concentrations at the age of 15 or 16 years, however, were accompanied by significant improvement in cognitive test results; mean IQ increased from 106 to 112 (p = 0.002). Patients with greater improvement in hormonal values had significantly greater improvement in IQ.


CONCLUSIONS
The prevalence of noncompliance in the adolescent children of our cohort with congenital hypothyroidism was high. Subsequent improvement in thyroid control was associated with significant improvement in psychometric test scores.
D000293:Adolescent; D015331:Cohort Studies; D003409:Congenital Hypothyroidism; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy / Q000523:psychology; D007360:Intelligence; D007361:Intelligence Tests; D012044:Regression Analysis; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use; D016312:Treatment Refusal
D013972:Thyrotropin; D013974:Thyroxine