June 9, 2023: Metformin, a cheap and widely-used diabetes drug, reduces the incidence of long Covid by nearly 40 per cent in patients suffering from acute Covid-19, according to a new study.
In a randomised controlled phase III trial of 1126 people, researchers found that if metformin was given within three days of testing positive for SARS-CoV-2 for two weeks, it led to 40% fewer long Covid diagnoses over the following 10 months compared with people who were prescribed a placebo.
The participants were chosen based on their risk profile for Covid-19, such as being overweight and blood pressure. The median age of participants was 45 years; 44% were male and 56% were female. The trial was conducted between December 2020 and January 2022 in the US, hence it included the Omicron variant, which research says does not have a propensity for long covid.
The cumulative incidence of long Covid by day 300 was 6.3% (35 of 564) in participants given metformin compared with 10.4% (58 of 562) in those receiving placebo (hazard ratio 0.59, 95% confidence interval 0.39-0.89; P=0.012). The prognosis was better in people who were given metformin within three days of symptom onset than in those who started metformin four days or longer after symptom onset.
Other recommended Covid medicines such as ivermectin and fluvoxamine were found to be ineffective in decreasing the risk of long covid.
Symptoms of long covid include breathlessness, chronic fatigue, “brain fog,” anxiety, and stress. Currently, there are no proven treatments for long Covid. The World Health Organization estimates that long covid affects one in 10 people who get Covid.
The researchers cautioned that they did not test metformin on people who had already been diagnosed with long Covid, so the findings did not mean it could be used to treat the condition.
“Previous studies have found that metformin stops the SARS-CoV-2 virus from replicating in the lab, which is consistent with predictions from our mathematical modelling of viral replication, so that might be what is causing the reduction in both severe covid-19 and long covid diagnoses seen in this trial,” said co-author David Odde, a University of Minnesota biomedical engineer.
Studies show that around 10–20% of people infected by SARS-CoV-2 may go on to develop symptoms that can be diagnosed as long COVID. Although exact numbers of those living with the condition are uncertain, it is believed that more than 17 million people across the WHO European Region may have experienced it during the first two years of the pandemic (2020/21).
A study by the Centers for Disease Control and Prevention shows that long Covid was the reason for 3,544 deaths in the United States between January 2020 and June 2022. “A lot of people think of long covid as associated with long-term illness,” said Farida Ahmad, a health scientist at the Centers for Disease Control and Prevention while speaking about the effects of long Covid and lead author of the study. “This shows it can be a cause of death.”
The percentage of people who have had Covid and currently report long Covid symptoms declined from 19% in June 2022 to 11% in January 2023, according to the latest US government figures. Another study done in Israel found that most symptoms of long COVID resolved within a year, although that study was limited to people with mild illness.
The present study, published in Lancet Infectious Diseases, was funded by Parsemus Foundation, Rainwater Charitable Foundation, Fast Grants, the UnitedHealth Group Foundation, and National Institutes of Health.