7/n I don't agree that preprints would necessarily reduce the risk of publication bias in this context - people may be less likely to preprint null results because no one is going to care very much
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18/n If the study had a MUCH bigger proportion of people who had PCR +ve COVID-19 receiving the intervention, that's not a great sign wrt the allocation concealment procedures (which aren't that well described either)
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19/n This sort of finicky examination is where it gets really, really tough, because like I said, it's a bit subjective. I don't really care either way about the studies included, but people can (and probably will) disagree
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20/n That being said, I quickly redid the meta-analysis excluding these two quite weird studies, and the results completely change, with no significance at all (RR 0.72, 0.41-1.25) Make of that what you willpic.twitter.com/8ucUe40gq3
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21/n Even if you ignore my opinions, limiting the analysis to only studies rated BY THE AUTHORS as "low" risk of bias gives you a completely inconclusive result (RR 0.65, 0.12-3.59)
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22/n So I don't really have an issue with the methodology or the results of the study, except to say that I think the risk of bias here is generally quite high and publication bias is likely The conclusions however...
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23/n I don't think this is justified at all to be honest. Even if we ignore the issues that I mentioned in this thread, most of these studies are really short (probably because they're all preprints) containing only a fraction of the information you need to properly assess thempic.twitter.com/8tX77GMESA
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24/n There's a good reason the risk of bias for so many regions here is 'unclear' - the studies simply don't include enough information! Often the methods sections are 3-4 paragraphs long (v. short for an RCT)pic.twitter.com/8AP18DKtD2
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25/n Moreover, publication bias looks to be a bit of an issue, and it's not really addressed. Quite likely to be some null findings that are floating around but will be published eventually!
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26/n On top of this, if you only look at studies that the authors have rated as having a low risk of bias for all domains, the evidence is pretty much squarely null, although this is limited by the fact that there are only 3 good studies
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27/n I don't think that this study really supports the use of ivermectin as a treatment for COVID-19 outside of a clinical trial, which is a shame because it'd be fantastic to have another effective drug for the disease
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28/n The depressing thing is that 100s of millions of people, mostly in developing countries, have had ivermectin for COVID-19, and yet we've only got 3 low-risk studies with <700 participants total to use as good evidence


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29/n Oh, one other point is that the authors considered the Fonseca study an "outlier" because exclusion lowered the I^2, which I don't understand because excluding the Elgazzar study lowers the I^2 a lot as well
pic.twitter.com/49WMIzgXWe
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30/n Also, I should reiterate that while I disagree with the conclusions, the study itself is pretty strong. The methodology was well constructed, I have few if any criticisms of the actual research the authors conducted
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End of conversation
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