We read with interest the recent article by Nirmal, et al. [1]. We congratulate the authors for carrying out this study, which definitively clearified some issues related to the long-term use of inhaled corticosteroid (ICS) in children. However, we want to highlight some points related to this article.

In this study, the ratio of the case (n=75) to control (n=25) was only 3:1, which may decrease the statistical power of the study and make a comparison between the groups difficult. For optimal statistical power, at least a 1:1 ratio is suggested. The number of controls rather than cases increase the statistical power, but this effect is negligible after the case to control ratio 1:4 [2].

Allthough it was not the objective of this study to look at fungal colonization, but fungi also form an important component of nasopharyngeal flora. ICS is well known to enhance fungal colonization in naso-oropharynx [3]. Hoarseness of voice and oropharyngeal candidiasis are known side effects of ICS as a result of fungal colonization [4]. Therefore, it would have been interesting if the authors had also considered fungal colonization in this study.

It is essential to look at adherence to ICS therapy since poor adherence might have a nasopharyngeal flora similar to control group. Authors should have given information on adherence to therapy in the study participants.

1. Nirmal G, Awasthi S, Gupta S, Aggarwal J. Effect of different doses of inhaled corticosteroid on the isolation of nasopharyngeal flora in children with asthma. Indian Pediatr.2019;56:913-6.

2. Hennessy S, Bilker WB, Berlin JA, Strom BL. Factors influencing the optimal control-to-case ratio in matched case-control studies. Am J Epidemiol. 1999;149:195-7.

3. Fukushima C, Matsuse H, Tomari S, Obase Y, Miyazaki Y, Shimoda T, et al. Oral candidiasis associated with inhaled corticosteroid use: comparison of fluticasone and beclomethasone. Ann Allergy Asthma Immunol. 2003;90:646-51.

4. Hossny E, Rosario N, Lee BW, Singh M, El-Ghoneimy D, Soh JY, et al. The use of inhaled corticosteroids in pediatric asthma: an update. World Allergy Organ J. 2016:12:26.