Papers that were withdrawn were removed from the Ivmmeta study. The OP's author dismisses studies outright for various subjective reasons. He doesn't mention 43 of the studies and simply starts with 30 of the 73. Out of those thirty he dismisses studies for various reasons such as" I don't have a great understanding of this one but I don't trust it at all. Luckily it is small and non-randomized so it will be easy to ignore going forward." And "it's too confusing to interpret." And "it's hard to tell from the paper who was on how much of what, and the discussion of ivermectin seems like kind of an afterthought after discussing lots of other meds in much more depth." And "the study excluded people with high viral load, but the preregistration didn't say they would do that." Yet, the author keeps studies (Lopez-Medina) for which he has this to say:Zobel said:
Inclusion criteria is a part of any meta analysis. Excluding studies for reasons like "this study is fraudulent and certainly never happened" or "this study has impossible numbers in the results" or "this study changed outcomes midway to produce a favorable result" is a good thing, not a bad one.
If you want to criticize the analysis done, you should do so on the basis of the exclusion criteria being used - that is to say, when a paper is excluded for a given reason, you should state why you think it should be included. Simply calling it selection bias is a waste of time.
"They originally worried the placebo might taste different than real ivermectin, then solved this by replacing it with a different placebo [in mid-study] ... Primary outcome was originally percent of patients whose symptoms worsened by two points, as rated on a complicated symptom scale when a researcher asked them over the phone. Halfway through the study, they realized nobody was worsening that much, so they changed the primary outcome to time until symptoms got better, as measured by the scale... In order to get as big as it did, Lopez-Medina had to compromise on rigor. Its outcome is how people self-score their symptoms on a hokey scale in a phone interview, instead of viral load or PCR results or anything like that."
Yet, in the end he kept the study. It happened to be one of the few, albeit larger studies, which did not find any Ivermectin efficacy in treating Covid. Hmmm. An open letter, signed by >100 physicians, concluding this study is fatally flawed can be found here. A subjective selection criteria is textbook selection bias.
https://jamaletter.com