We read with interest the study on predicting the course of
hypothyroidism based on initial thyroid stimulating hormone (TSH) levels
and dose of L-thyroxine at 12 and 24 months [1]. This is a common
dilemma faced by the clinicians while treating congenital hypothyroidism
and deciding on the extent of work-up needed. We have two observations
in this well conducted study.
The female gender prediliction noted to an extent of
2:1 is very interesting. Although there is some female prediliction
noted in the studies, most of it is non-significant [2]. It would be
interesting to explore the reason for such a high female prediliction in
this cohort.
The TSH cut-off used to diagnose congenital
hypothyroidism and start thyroxine replacement therapy was 10 µIU/mL,
while recent guidelines suggest a cut-off of 20 µIU/mL [3]. This could
have three consequences: (i) the number of cases labelled as
transient hypothyroidism (TH), but not permanent hypothyroidism (PH),
can increase because of lowered cut-off as shown in some previous
studies [4]; (ii) there is a risk of overtreating euthyroid
neonates and a possible increase in behavioural problems in later life
[5]; and (iii) the difference in TSH levels at diagnosis could
have achieved statistical significance because of possible inclusion of
euthyroid neonates in TH group, a finding not noted in previous studies.
References
1. Scavone M, Carboni E, Stefanelli E, Romano G, Vero
A, Giancotti L, Miniero R, et al. Prediction of transient or
permanent congenital hypothyroidism from initial thyroid stimulating
hormone levels. Indian Pediatr. 2018;55: 1059-61.
2. DeMartino L, McMahon R, Caggana M, Tavakoli NP.
Gender disparities in screening for congenital hypothyroidism using
thyroxine as a primary screen. Eur J Endocrinol. 2018;179:161-7.
3. Léger J, Olivieri A, Donaldson M, Torresani T,
Krude H, Van Vliet G, et al. European Society for Paediatric
Endocrinology Consensus Guidelines on Screening, Diagnosis, and
Management of Congenital Hypothyroidism. Hormone Res Pediatr.
2014;81:80-103.
4. Kara C, Günindi F, Yýlmaz GC, Aydýn M. Transient
congenital hypothyroidism in Turkey: An analysis on frequency and
natural course. J Clin Res Pediatr Endocrinol. 2016;8:170.
5. Bongers-Schokking JJ, Resing WC, Oostdijk W, de Rijke YB, de
Muinck Keizer-Schrama SM. Relation between early over-and undertreatment
and behavioural problems in preadolescent children with congenital
hypothyroidism. Hormone Res Pediatr. 2018;90:247-56.
