Ivermectin meta-analysis – the background

Written by | 25 Jan 2021 | COVID-19

IMI interviewed Dr Tess Lawrie, Director of the Evidence-based Medicine Consultancy Ltd, to find out more about her recently-published meta-analysis of ivermectin trials for covid-19.


The Evidence-based Medicine Consultancy Ltd is an independent medical research company that specialises in evidence synthesis to support clinical practice guidelines.

On Boxing Day Dr Lawrie received a link to the video of Dr Pierre Kory’s testimony to the US Senate Committee on Homeland Security and Governmental Affairs – something that she found very moving. “Here’s a doctor having to ask permission to treat patients with a very well-known medicine that has been around for the past 40 years”, she says. As a doctor herself, who trained in South Africa she was used to not having the medicines that she needed. ”My heart went out to Dr Kory. I thought – I can see a desperate doctor there, and I‘ve been there, I know what it’s like to be able to save patients but just not have the tools to do so”, she says.

Dr Kory and his colleagues in the Frontline Covid-19 Critical Care (FLCCC) Alliance had reached the conclusion that ivermectin was very effective in preventing and treating covid-19. They then appealed to the international health care community and medicines‘ agencies to review their findings independently and take action. Sensing the urgency of the task and knowing that it could be a lengthy process Dr Lawrie decided to re-analyse the data herself over the Christmas holiday period. She downloaded all the papers and excluded those that were not of good enough quality for inclusion in a meta-analysis.  All the remaining trials were evaluated for risk of bias and the data were extracted and fed into Review Manager software.

Only clinical outcomes were included in the analysis (rather than biochemical outcomes).  In general, health outcomes are most important to people. They need to know whether a treatment will make them me feel better, prevent disease or prevent them from dying. Death was considered to be the most important outcome – and it has the advantage of being an objective endpoint [in trials].

“I was amazed at what I found”, she recalls. A total of ten trials is included in the analysis, but for the main outcome of death there are six randomised controlled trials (RCTs). Observational controlled trials were also included. Although these are not normally included in Cochrane reviews, on this occasion Dr Lawrie decided to use the trials that had been included in Kory’s original review. She emphasises that only the high-quality observational studies were included, the lower quality studies had already been excluded.

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