COVID-OUT, a 1125 person trial, looked at the effect of 3 drugs used to treat acute COVID and whether the participant developed “Long COVID” afterwards.
Personally I think that the Long COVID rate - 8.4% (94/1125) - looks too high if you define Long COVID as the highly-debilitating multi-symptom syndrome that makes up Long COVID support groups. But let’s suppose for the sake of argument that the COVID-OUT trial is correct about metformin reducing the odds of “Long COVID” developing. Then the question becomes…
Here is data from the Patient Experiences Survey.
29 people provided data on metformin. 19 of those people self-identified as Long COVID. These people were recruited from online support groups, so most of them have debilitating multi-symptom syndromes.
There is risk to the treatment as several reported mild or significant worsening. Others reported improvement. If you apply numbers to improvement and worsening, metformin is in the bottom 10% of all treatments due to the high rate of people reporting worsening. For most treatments, very few people report any type of worsening.
None of the 29 people were mostly recovered and reported metformin as leading to significant improvement. So it didn’t seem to contribute to recovery in any of the 29 people who tried it.
This does not look like a promising treatment for people who already have chronic illness, although 29 people is a small sample size and not enough to draw a definitive conclusion.
The high rate of reported worsening is worrying and suggests that this drug is among the riskier drugs out there. This may be one of the drugs that chronic illness patients react to at a higher rate than healthy people.