Re: Thyroid Dysfunction in Children with Idiopathic 
Nephrotic Syndrome Attending a Paediatric 

Hospital in Qazvin, Iran

Sultan Qaboos University Med J, May 2021, Vol. 21, Iss. 2, pp. e332, Epub. 21 Jun 21
Submitted 6 Jan 21
Revision Req. 16 Feb 21; Revision Recd. 28 Feb 21
Accepted 9 Mar 21

This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

https://doi.org/10.18295/squmj.2021.21.02.030

LETTER TO THE EDITOR

Dear Editor, 

I read with interest the case-control study by Saffari et al. published in the November 2020 issue of SQUMJ.1 
Among a cohort of Iranian children, Saffari et al. compared thyroid hormone levels between patients with 
nephrotic syndrome (NS) and healthy controls as well as between patients with NS in the active stage of the disease 
and those in remission. They found that increased thyroid-stimulating hormone (TSH) levels were more common 
in patients with NS in comparison with controls (34.2% versus 10.8%; P = 0.001). A significantly lower number of 
patients with active disease were euthyroid in comparison with those in remission (51% versus 95.8%; P = 0.001). 
Furthermore, 9.5% of patients in the active and no patient in the remission stage had abnormal free thyroxine 
levels (P <0.001), while 14.3% and 0% had highly increased TSH levels, respectively (P = 0.002).1 In patients with 
NS, the rates of subclinical hypothyroidism (34.7%) and overt hypothyroidism (14.3%) were significantly higher 
compared to controls (4.2%; 0% respectively; P = 0.001). Based on the reported prevalence of subclinical (34.7%) 
and even overt hypothyroidism (14.3%), Saffari et al. recommended that thyroid screening tests might be needed 
for patients with NS.1 They also mentioned two study limitations, namely small sample size and short follow-up 
period that did not allow adequate detection of hypothyroid subsidence in cases of subclinical hypothyroidism. It 
is worth mentioning that the correct evaluation of thyroid health status is centred on the use of suitable reference 
intervals (RI) of the thyroid function tests (TFT) to evaluate the readings of different components of TFT. There 
are certain determinants of RI of TFT for a particular population that must be taken into consideration such 
as age, gender, body mass index and genetic variants.2  Iran is among the pioneer countries that have already 
formulated their own RI of TFT to be utilised in researche centres and clinical fields.3 Instead of using a local 
standard, Saffari et al. mentioned in the study methodology that they referred to the foreign RI of TFT to define 
subclinical hypothyroidism and hypothyroidism.4,5 Accordingly, this limitation might question the accuracy of the 
study results and recommendation.

Mahmood D. Al-Mendalawi
Department of Paediatrics, Al-Kindy College of Medicine, University of Baghdad, Baghdad, Iraq 
E-mail: mdalmendalawi@yahoo.com

References
1. Saffari F, Ahadi S, Dalirani R, Esfandiar N, Yazdi Z, Arad B. Thyroid Dysfunction in Children with Idiopathic Nephrotic Syndrome Attending 

a Paediatric Hospital in Qazvin, Iran. Sultan Qaboos Univ Med J 2020;20:e332–8. https://doi.org/10.18295/squmj.2020.20.04.009.

2. Chaker L, Korevaar TI, Medici M, Uitterlinden AG, Hofman A, Dehghan A, et al. Thyroid Function Characteristics and Determinants: The 
Rotterdam Study. Thyroid 2016;26:1195–204. https://doi.org/ 10.1089/thy.2016.0133. 

3. Mansourian AR, Ahmadi AR, Saifi A, Bakhshandehnosrat S. The children reference range of thyroid hormones in Northern Iran. Pak J Biol 
Sci 2010;13:862–5. https://doi.org/10.3923/pjbs.2010.862.865. 

4. Crisafulli G, Aversa T, Zirilli G, Pajno GB, Corica D, De Luca F, et al. Subclinical hypothyroidism in children: When a replacement hormonal 
treatment might be advisable. Front Endocrinol (Lausanne) 2019; 10:109. https://doi.org/10.3389/fendo.2019.00109.

5. Ito S, Kano K, Ando T, Ichimura T. Thyroid function in children with nephrotic syndrome. Pediatr Nephrol 1994; 8:412–15. https://doi.
org/10.1007%2FBF00856516.

e332 | SQU Medical Journal, May 2021, Volume 21, Issue 2

https://creativecommons.org/licenses/by-nd/4.0/
https://doi.org/10.18295/squmj.2020.20.04.009
https://doi.org/%2010.1089/thy.2016.0133
https://doi.org/10.3923/pjbs.2010.862.865
https://doi.org/10.3389/fendo.2019.00109
https://doi.org/10.1007%252FBF00856516
https://doi.org/10.1007%252FBF00856516