Age, birth weight adjustments improve congenital adrenal hyperplasia screening program in Brazil
Click Here to Manage Email Alerts
By adjusting the age and birth weight at which health care providers collected neonatal 17-hydroxyprogesterone samples from newborns, as well as basing neonatal 17-hydroxyprogesterone cutoff levels on the 99.8th percentile, a congenital adrenal hyperplasia screening program for newborns in Brazil improved efficacy, study data showed.
“The [congenital adrenal hyperplasia newborn screening program] shows high efficacy of detection in severe cases; however, the [false-positive result] rate of 0.4% to 9.3% from these tests is a significant concern,” Giselle Y. Hayashi, of the Associação de Pais e Amigos dos Excepcionais de São Paulo, and colleagues wrote. “Therefore, protocols that consider the physiological variation in neonatal 17-hydroxyprogesterone (17-OHP) values have been suggested, adjusting the 17-OHP cutoff values for gestational age and/or birth weight. However, data concerning the optimal cutoff values of blood 17-OHP … are conflicting.”
Researchers evaluated 17-OHP levels from 271,810 newborns divided into two groups: samples from infants aged 48 to less than 72 hours and those aged at least 72 hours. Hayashi and colleagues divided those groups into four subgroups: birth weight 1,500 g or less; 1,501 g to 2,000 g; 2,001 g to 2,500 g; and more than 2,500 g.
The group aged 48 to less than 72 hours had lower 17-OHP levels in all weight groups (P < .001), the researchers reported. The false-positive rate was 0.2% using the 99.8th percentile, and 0.5% with the 99.5th percentile. Hayashi and colleagues wrote that the 99.8th percentile was the best 17-OHP cutoff. Researchers diagnosed 44 cases of salt-wasting and five cases of simple virilizing congenital adrenal hyperplasia. The infants’ 17-OHP levels ranged from 93.3 nmol/L to 2,209.8 nmol/L. Among 29 newborns included in the false-positive rate, two were determined to have a nonclassical form of congenital adrenal hyperplasia.
“[Congenital adrenal hyperplasia newborn screening] is an important advance in establishing an early diagnosis of [congenital adrenal hyperplasia] and preventing morbidity and mortality,” the researchers wrote. “However, the [newborn screening] program still faces problems that mainly relate to the economic and psychosocial costs associated with false-positive results. Considering these factors, we conclude that adjusting [neonatal] 17-OHP levels by sample collection time and birth weight allows a reduced [false-positive rate] and improves [newborn screening congenital adrenal hyperplasia] efficacy. To prevent late diagnosis and the development of salt-wasting crises, we recommend that the sample collection should be performed between 48 and 72 hours. Additionally, we suggest that adoption of [neonatal] 17-OHP values based on the 99.8th percentile further improves [newborn screening congenital adrenal hyperplasia] efficacy.” – by Andy Polhamus
Disclosure: The researchers report no relevant financial disclosures.