Common diabetes drug linked to lower risk of death after COVID infection
Laine BergesonToday at 3:49 p.m.
COVID-19
People with type 2 diabetes who were taking the drug metformin when they contracted COVID-19 had a 39% lower risk of dying over the following year than peers who were taking a different diabetes medication, according to a study published last week in Diabetes, Obesity and Metabolism.
The study also found that those who were taking metformin, a medication that helps lower blood sugar and improve insulin sensitivity, had a slightly reduced but non-statistically significant risk of long COVID.
The findings come on the heels of a study published last week that found that COVID patients who were prescribed metformin within six days of infection were less likely to develop long COVID or die.
Metformin is one of the most commonly prescribed drugs for people with diabetes and prediabetes. Researchers hypothesize that the drug’s antiviral, anti-inflammatory, and anti-hyperglycemic properties help protect people from the persistent health problems that some people experience after recovering from an acute COVID infection.
Mortality risk 39% lower with metformin
For the study, researchers led by a team at Stanford University analyzed data from 53,332 US adults with type 2 diabetes who were diagnosed as having COVID from October 2021 to November 2023. Participants were 30 to 85 years old and had been prescribed either metformin or dipeptidyl peptidase-4 inhibitor (DPP4i), another diabetes drug, at least 30 days before their COVID diagnosis.Of the participants, 50,965 were prescribed metformin, and 2,367 were prescribed DPP4i. Fifty-two percent of those who took metformin and 59% of those who took DPP4i were women. The average age of metformin users was 60 years, compared with 64 for DPP4i users.
After adjusting for confounding factors, the researchers found that metformin use was associated with a 39% lower 12-month mortality risk (adjusted risk ratio [aRR], 0.61). Those who took metformin also had a 13% lower risk of long COVID (aRR, 0.87). However, the team found no statistically significant association between metformin use and a long-COVID diagnosis (aRR, 0.90).
The authors note that the findings are consistent with previous research linking metformin use during acute COVID infection with fewer emergency department visits, hospitalizations, and deaths.
Blood sugar control, reduced inflammation
Metformin may help protect people with type 2 diabetes from severe post-COVID outcomes in several ways. By lowering blood sugar, the drug may strengthen the body’s immune response and regulate the renin-angiotensin system, a pathway that plays a role in COVID severity.“Metformin's improvement of glycaemic control and insulin sensitivity may partially normalize this pathophysiological environment,” write the researchers. Metformin may also help tamp down the body’s inflammatory response and reduce viral load.
The study had some limitations. Patients taking DPP4i tended to be older and to have more comorbidities, which could influence outcomes. The team also could not adequately account for COVID vaccination history.
Still, the findings add to a body of evidence that suggests metformin may reduce severe COVID outcomes.
“These findings provide modest support for prescribing metformin for individuals with [type 2 diabetes] during acute COVID-19 to reduce post-COVID-19 mortality, although further investigation is needed to evaluate its impact on Long COVID and assess causality,” the authors conclude.
