Endocrine Abstracts

Background: Some children diagnosed with Congenital Hypothyroidism (CHT) have a transient form of the condition and do not require lifelong levothyroxine. It is currently recommended that children without a definitive diagnosis of permanent CHT should be re-evaluated at age 3 years. Studies investigating transient CHT either have high exclusion rates from drop-out in follow-up, or are small single centre studies. In Manchester, after initial assessment at the referral centre (Royal Manchester Children’s Hospital), subsequent follow-up is at the local hospital managed by a clinical network of paediatricians linked with the referral centre.

Methods: All children diagnosed with CHT following newborn screening (NBS) in Manchester were followed up with an annual survey to the responsible paediatrician. At the age of 3 years, children with gland in-situ, levothyroxine dose <50 µg/day and TSH below the top of the reference interval were recommended for re-evaluation.

Results: Over a 4-year study period (April 2015 to March 2019), 217,696 babies were screened for CHT and 183 children received a CHT suspected result from NBS (1 in 1190). After initial assessment, 159 children were started on levothyroxine (1 in 1369). Seven children were excluded over the study period because they moved out of the area or died; one child was lost to follow-up. Of the 152 children included, 68 were deemed suitable for re-evaluation as per pre-determined criteria. Following re-testing, 50 (74% fitting eligible criteria, 33% for whole group) eligible children had a successful trial off levothyroxine and did not require further outpatient review. However, 18 re-commenced medication and continued long-term outpatient review.

Conclusion: A clinical network approach to systematic follow-up of longer term CHT outcomes enabled longitudinal data collection in >95% of a cohort referred to the NBS programme in Manchester with finding of a significant proportion (33%) with transient CHT, optimising compliance with national guidelines. Roll out of a similar system across the UK could be facilitated by digital implementations like that used for sickle cell disease newborn outcomes.