High yield of congenital hypothyroidism among infants attending Children Hospital, Nairobi, Kenya. Facility based study in the absence of newborn screening.

Objectives: Congenital hypothyroidism (CHT) is a treatable cause of intellectual disability. Late diagnosis and delayed initiation of treatment leads to irreversible neurodevelopmental and intellectual disability. Thus, newborn screening is crucial. However, 71 % of babies are born in an area with no established newborn screening program and Kenya is not an exception. We aimed to determine the incidence of CHT, developmental outcomes of patients in the absence of newborn screening.

Methods: A retrospective data of subjects who met the inclusion criteria, newborn and infants from 3 days to 2 years whose thyroid function test (TFT) was undertaken during well baby visit or clinical suspicion of CHT were collected. Laboratory reference range for age was used to interpret the result and TSH>10 Uiu/mL after 6 weeks of life is considered abnormal according to ESPE guideline. Developmental outcome of children was collected from patient file documented by primary physician and parental concern.

Results: Of 1,426 children met inclusion criteria, 90 had elevated TSH. Out of which 70 repeat TFT showed normal TSH and free T4. The incidence of abnormal TSH across the different age groups was 2.4 , 7.2 and 10.5 % for ages 0-29 days, 1-11 months, and 1-2 years, respectively with p-value of =0.0002. While 20 cases with CHT identified with incidence of 14 per 1,000 children (1.4 %; 95 % CI: 0.9-2.1 %). Out this 12 (60 %) had poor developmental outcomes. Down's syndrome was the common associated condition 9/20 (45 %). All cases were primary CHT.

Conclusions: This study shows high incidence of CHT in a small cohort of patients over 5-year period with poor development outcome.