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August 17, 2022

In a recent article in Asthma and Allergy, Sohn et al discuss what the impacts were for patients with severe asthma who wore masks during the pandemic in South Korea.  Patients in the study were recruited from 5 university hospitals in 3 different regions of Korea between August 2020 and December 2020.  Thus far no study has assessed the effects of face masks on severe asthma.  The participants were given a questionnaire and also their wearing a Korean filter (KF)-94 mask which is equivalent to a U.S. N-95. Patients vital signs were measured via a 6 minute walk with and without the mask.

The paper goes on to publish some percentage results and then also provide some statistical comparisons by p-values without saying at all what statistical tests were used.  Even in their Figure 1, they just say they used GraphPad Prism and again without specifying the statistical tests used in that software. It is only once I clicked on their link for Supplementary Table I  that then a Word document with their methods in more complete detail came up.  In this they then stated that the Kruskal-Wallis test was performed to compare their Likert scale from their survey and the Mann-Whitney-U test was used to compare other continuous data and the Fisher’s Exact test was used for other categorical data.  They used a significance level of 0.05 like almost everyone else.  It is unclear why they used the K-W test because it is unclear what are the more than 2 groups and also why weren’t they using methods with paired data when they didn’t have a comparison or control group?  They treated the patients like they were independent or their own data.

They did find that wearing a mask significantly lowered oxygen saturation as compared to not wearing a mask but was still within a normal physiologic range.  Also, if severe asthma patients experienced dyspnea or headaches then they could switch from a KF-94 to a surgical mask, which are easier to wear. Finally they admit their study had limitations like it only focused on patients with severe asthma without a comparison or control group.  Also, we I already pointed out, their data analysis is flawed so how can we possibly trust the results from this study.

Written by,

Usha Govindarajulu

Keywords: COVID-19, statistics, South Korea, face masks, severe asthma, oxygen saturation


Sohn K-H, Lee M-N, Sim DW, Kim S, Cho YS, Kwon H-S, and Kim S-H. (2022). “Impact of wearing face masks on patients with severe asthma during the COVID-19 pandemic”. Journal of Asthma and Allergy.  2022:15.