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Age, birth weight adjustments improve congenital adrenal hyperplasia screening program in Brazil
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.