Congenital Hypothyroidism May Be Missed in a Significant Number of Infants

Results from a new study suggest that the management of congenital hypothyroidism may be suboptimal in newborns.¹

According to study investigators, between 2006 and 2015 in Utah, the American Academy of Pediatrics (AAP) guidelines regarding screening for and treatment of congenital hypothyroidism in newborns were not always met. This resulted in increased long-term disability due to the delayed diagnosis and inadequate treatment of the condition.

The study was presented at the 86th Annual Meeting of the American Thyroid Association (ATA).

The researchers looked at all the thyroid-stimulating hormone (TSH) values from two-thirds of all babies born in Utah between 2006 and 2015. The goal was to develop a normal range of TSH values in infants and children.  

“We were surprised to find that 50% of infants with congenital hypothyroidism had a delayed diagnosis of congenital hypothyroidism and 50% of children with congenital hypothyroidism were inadequately treated. A child with untreated congenital hypothyroidism will permanently lose up to half of an IQ point per day during the first month of life,” study investigator Joel Ehrenkranz, MD, director of diabetes and endocrinology at Intermountain Healthcare in Murray, Utah, told Endocrinology Advisor.

The AAP recommends measuring TSH in all newborns so that infants with congenital hypothyroidism are diagnosed by 14 days of life,² noted Dr Ehrenkranz. The association also recommends initiating immediate treatment with the goal of serum TSH lower than 5 mIU/L within 1 month of starting thyroxine replacement.² The goal of the study conducted by Dr Ehrenkranz and colleagues was to assess whether the diagnosis and treatment of infants with congenital hypothyroidism in Utah corresponded to AAP guidelines.

The team obtained TSH measurements between 2006 and 2015 in 4394 children younger than 2. TSH was measured using a third generation chemiluminescent immunoassay.  

The researchers found that the number of TSH measurements per infant varied from 1 to 18. An infant’s first TSH measurement was designated the initial TSH and those thereafter were designed subsequent TSH measurements.

The study showed that 82 of the 4394 (1.9%) infants referred for TSH measurement had an initial TSH of 20 mIU/L or greater.¹ In addition, 43 infants (1.0%) were found to have an initial TSH of 20 mIU/L or greater by day 14 of life.¹

The researchers discovered that delayed diagnosis of congenital hypothyroidism occurred in 39 out of 82 (48%) infants referred for TSH immunoassay.¹ Additionally, 42 out of 82 (51%) infants with congenital hypothyroidism were inadequately treated based upon TSH greater than 5 mIU/L 1 month or more after the initial TSH of 20 mIU/L or greater.¹ The study also showed that 39 infants had a delayed diagnosis of congenital hypothyroidism, defined as an initial TSH of 20 mIU/L or greater in an infant older than 14 days.¹

“Endocrinologists need to be aware that newborn screening programs for congenital hypothyroidism miss the diagnosis in 10% of babies and that it is essential to identify this disease as early as possible and monitor treatment closely to insure that an affected infant can achieve his or her maximal cognitive potential,” Dr Ehrenkranz told Endocrinology Advisor.

He and his colleagues concluded that the management of congenital hypothyroidism in Utah between 2006 and 2015 did not meet the AAP guidelines. Subsequently, this may result in increased long-term disability due to the delayed diagnosis and inadequate treatment of congenital hypothyroidism.

“This is the first study to look at the quality of care of infants with congenital hypothyroidism on a state-wide level using the American Academy of Pediatrics Guidelines as a metric. The findings are important because the delayed diagnosis and inadequate treatment of congenital hypothyroidism is a major public health problem that affects approximately 1 in 3000 babies worldwide,” said Dr Ehrenkranz.

The eradication of cretinism in the industrialized world represents one of the greatest public health triumphs of the 20th century. Health professionals must continue to pay attention to ensure that every child with congenital hypothyroidism is diagnosed by 2 weeks of age and is adequately treated as soon as possible, noted Dr Ehrenkranz.

Disclosures: Dr Ehrenkranz reports no financial relationships or commercial interests.

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References

1. Ehrenkranz J, Butler A, Snow G, Bach P. Oral Abstract 19. The diagnosis and treatment of congenital hypothyroidism in Utah 2006-2015. Presented at: American Thyroid Association Annual Meeting; September 21-25, 2016; Denver, Colorado.
2. American Association of Pediatrics, Rose SR, American Thyroid Association, Brown RS, Wilkins L, Pediatric Endocrine Society. Update of newborn screening and therapy for congenital hypothyroidism. Pediatrics. 2006;117(6):2290-2303. doi:10.1542/peds.2006-0915.