We are thankful to the reader for raising some issues for discussion
regarding the association of allergic rhinitis (AR) and sinusitis with
childhood asthma [1].
First, regarding the diagnosis of asthma and use of
spirometry, it has already been mentioned in the paper that asthma was
diagnosed based on history and clinical examination as per the National
Asthma Education and Prevention program II (updated 2002). Spirometry is
not a diagnostic modality for asthma, and was not used in this study.
Second, regarding the sampling technique, considering
the cross-sectional nature of the study to find out the point prevalence
of AR and sinusitis in childhood asthma, asthma cases visiting first
time to the clinic were enrolled. As the children visiting to the clinic
randomly (without choice/selection of the investigator), it fits into
probability sampling. The main objective of the study was to find the
association of AR and sinusitis in children with different type of
asthma severity. A formal sample size calculation was not made as there
was no previous study on sinusitis employing the CT scan criteria for
diagnosis in asthmatic children. As described earlier, sample size
calculation may be prone to error if choices of parameters for
calculation are not proper [2].
Third, it has been already mentioned in the paper,
for severity determination, persistent asthma (mild and moderate) was
made as one group, as a result binomial logistic regression was applied.
Fourth, regarding the diagnosis of sinusitis, it was
already mentioned in the paper that all the five children with clinical
suspicion of sinusitis were having sinusitis confirmed on CT scan. We
did not perform CT scan in children having no clinical suspicion of
sinusitis.
References
1. Chinnakkannan SK, Singh M, Das RR, Mathew JL,
Saxena KA. Association of allergic rhinitis and sinusitis with childhood
asthma. Indian Pediatr. 2016:54:21-4.
2. Noordzij M, Tripepi G, Dekker FW, Zoccali C, Tanck
MW, Jager KJ. Sample size calculations: basic principles and common
pitfalls. Nephrol Dial Transplant. 2010;25:1388-93.