Researchers published the study covered in this summary on medRxiv.org as a preprint that has not yet been peer reviewed.
In a longitudinal study of 572 adults with type 2 diabetes, after adjustment for potential confounders metformin use was significantly associated with improved myocardial perfusion reserve (MPR), a measure of coronary microvascular function, and longer survival.
Why This Matters
Cardiovascular disease is the most common cause of death in people with type 2 diabetes.
Metformin is the most widely used glucose-lowering agent and has been recommended as first-line treatment for people with type 2 diabetes by several authoritative groups.
This is the first reported clinical study with findings that show significant association between metformin use and improved coronary microvascular function in adults with type 2 diabetes.
The results confirm previous reports that metformin treatment of adults with type 2 diabetes significantly associates with improved overall survival.
The study included 572 adults with type 2 diabetes who underwent quantitative, stress-perfusion, cardiovascular magnetic resonance imaging for clinical or research purposes at any of four United Kingdom centers during September 2016-May 2021. The study also included 52 age- and sex-matched, healthy controls with no history of cardiac disease or major risk factors.
The researchers used the results of the cardiovascular magnetic resonance imaging to estimate global myocardial blood flow (MBF) and MPR.
The researchers performed multivariable linear regression analyses to estimate how metformin use associated with stress MBF and MPR. They adjusted their model for factors known to be associated with differences in stress MBF and MPR.
At entry, 388 of the people with type 2 diabetes (68%) were on metformin treatment at baseline and 184 (32%) were not. Follow-up data were available for a median of 851 days following enrollment.
For MPR, the regression coefficient for metformin had a significant value of 0.12, which suggests that use of metformin associated with a significant increase in MPR. For stress MBF the regression coefficient for metformin suggested that the agent had no significant impact on this measure.
People with type 2 diabetes taking metformin had significantly lower rates of death, 2.3%, and stroke, 2.1%, compared with those not on metformin, who had a mortality rate of 8.7% and a stroke rate of 5.4%. The combined incidence rate of major adverse cardiovascular and cerebrovascular events did not differ significantly between the two subgroups.
After adjustment for age and left ventricular ejection fraction (LVEF), the hazard ratio for all-cause mortality was a significant 0.29 for those taking metformin compared with those not taking metformin.
This was an observational, nonrandomized study.
The study included a relatively small number of events and included a relatively large number of covariates.
Treatment of a fraction of the enrolled subjects with metformin may have introduced various selection biases.
The study's dependence on electronic medical records for patient data, an approach that may have resulted in missing data. In addition, the collection of some data for certain subjects never occurred.
The study received no commercial funding.
The authors report no relevant financial relationships.
This is a summary of the preprint research study "Metformin associates with improved myocardial perfusion reserve and survival in patients with Type 2 Diabetes Mellitus,” by researchers primarily affiliated with the University of Leeds, Leeds, UK, on medRxiv and provided to you by Medscape. It has not yet been peer reviewed. The full text of the study can be found on medRxiv.org.