Issues in COVID-19 research and statistical analyses (Part XVVXI)
May 25, 2022 In a recent article in The Mirror, the author gives a haunting statement that SARS-CoV-2 can cause cells to explode after entering cells which can lead to severe damage. The authors quotes a recent article in Nature from April 6 in which the researchers discuss the mechanism of
pyroptosis of cells infected by the virus, which is like a cell catching on fire and hence exploding. While pyroptosis kills the virus, then the remaining contents are released into the bloodstream of the person, namely cytokines are released and this leads to blood inflammation. The authors mention what statistical procedures they used in the footnote of each figure in the paper only. They say that “Parametric or nonparametric (Mann–Whitney U-test) twotailed unpaired t-tests were used to compare two unpaired groups. Multiple-group comparisons were analysed using one-way ANOVA with Sidak or Tukey multiple-comparisons tests, or nonparametric Kruskal–Wallis with Dunn post-test. Multiple groups were compared using twoway ANOVA with additional Sidak or Tukey multiple-comparisons test. Mean plasma values from hospitalized patients with COVID-19 on each day were compared between severity groups by multiple unpaired t-tests. Correlations of plasma levels were determined by simple linear regression and Pearson correlation coefficient.”. Why don’t the authors just say they used a nonparametric test, Mann-Whitney=U tests to compare 2 groups?? Also, why don’t they state what factors were used in their two-way ANOVA’s? Also why was it okay to run multiple unpaired ttests without adjustment for multiple comparisons like they did for their ANOVA post-hoc comparisons. It is very difficult to understand from each figure what was compared with what method since in each figure they put multiple plots or figures and so each is kind of small and very hard to read. Also, it would appear from most of the sample sizes that the n’s are fairly small like less than 10. In their discussion section, their summary of results says “About 10% of monocytes and 8% of lung macrophages in patients with COVID-19 were SARS-CoV-2-infected.” I am not sure how we are readers were to discern this from their results. No actual tables of values are presented in the article. Much of the article is about the supposed cell mechanisms and biology. I suppose the journalists found this article’s results inticing to publish about but statistically, it is very hard to discern.
Written by, Usha Govindarajulu Keywords: COVID-19, pyroptosis, inflammation
References Knibbs, Jessica (May 17, 2022) “Covid infection causes cells to 'explode' and damage multiple organs, study finds” Mirror. https://www.mirror.co.uk/lifestyle/health/covid-infection-causescells-explode-26985091 . Junqueira, C., Crespo, Â., Ranjbar, S. et al. FcγR-mediated SARS-CoV-2 infection of monocytes activates inflammation. Nature (2022). https://doi.org/10.1038/s41586-022-04702-4 https://www.drkarafitzgerald.com/wp-content/uploads/2020/03/Screen-Shot-2020-03-24-at8.28.45-PM-952x1024.png