medwireNews: The mortality rate in children with screen-detected congenital central hypothyroidism (CH-C) is elevated, but as the result of comorbidities rather than the condition itself, study findings show.

Researchers led by Nitash Zwaveling-Soonawala (Academic Medical Center, Amsterdam, the Netherlands) followed up 138 patients with CH-C detected by a national newborn screening programme between 1995 and 2013. The screening programme was based on measurement of thyroxine in all newborns with thyroid-stimulating hormone determination in the lowest 20% of T4 concentrations.

They found that 15 (10.9%) of these patients had died – nine within the first year of life and 14 before the age of 5 years. This gave infant and child mortality rates of 65.2 and 101.4 per 1000 children, respectively, compared with population rates of 4.7 and 5.4 per 1000 children.

However, the team also estimates that screening missed 27% of all CH-C cases. Accounting for these would reduce the overall mortality rate to 7.9%, although this is “still considerably higher” than the population rate for Dutch children, they say.

“Given the association between hypopituitarism and cerebral anomalies, an increased mortality in this subgroup of patients was to be expected and therefore the results of this study are not surprising”, write the researchers in The Journal of Clinical Endocrinology & Metabolism.

Just one patient died of an endocrine cause; this patient had multiple pituitary hormone deficiency (MPHD) and died of an adrenal crisis before the age of 1 year, which the researchers say emphasises the seriousness of MPHD.

MPHD was common in this cohort, affecting 59% of the patients. Other causes of death were congenital malformations, birth asphyxia and infections.

“Overall, CH-C was considered a comorbidity rather than the primary diagnosis in this group of deceased patients”, say Zwaveling-Soonawala and team.

They note that the mortality rate of CH-C patients in countries without screening programmes is unknown, but suggest that the apparently low prevalence of CH-C in these countries could be explained by patients dying early, of associated conditions, before CH-C is detected.

Eleanor McDermid

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