(RxWiki News) For those with diabetes, metformin not only helps to control blood sugar, but it may also boost heart health. The cardiovascular benefit, however, may not extend to those without diabetes.
Several investigations have shown that cardiovascular events may be less likely for diabetes patients who take metformin. In the UK Prospective Diabetes Study, overweight diabetes patients taking the medication cut their heart attack risk by 39 percent. Some have thought that this heart benefit may affect those without diabetes, but new research has shown that the therapy does not help heart attack patients who do not have the disease.
"Carefully review which medications to take after a heart attack."
Chris P. H. Lexis, MD, in the department of cardiology at the University of Groningen in the Netherlands, and colleagues followed 380 heart attack patients who did not have diabetes.
The patients had all suffered a type of heart attack called an ST segment elevation myocardial infarction (STEMI). These heart attacks are caused by a block in the blood supply over a prolonged period.
To restore blood flow, these individuals received percutaneous coronary intervention (PCI), a procedure to open narrowed coronary arteries that often involves placing a stent (mesh tubing) at the site of the blockage to keep an artery open.
For four months after the procedure, 189 patients received a placebo and 191 patients received metformin hydrochloride (500 mg) twice daily. Metformin is sold under the brand names Glucophage, Glumetza, Glucophage XR and Fortamet.
With STEMI, the left ventricle in the heart has a decreased ability to pump in up to half of patients, and up to 40 percent of patients may develop heart failure sometime after the episode.
The goal for Dr. Lexis and his team was to determine whether metformin helps preserve function in the left ventricle of the heart.
Scientists assessed how well the left ventricle pumped blood with each contraction by a measure known as left ventricular ejection fraction (LVEF), which was determined by magnetic resonance imaging.
After four months from the study start, there was no significant difference in LVEF between the metformin group and the placebo group.
An ejection fraction measurement of 55 to 70 percent is considered normal. Both metformin and placebo groups had LVEFs just below normal, with the metformin group at an average of 53.1 percent and the placebo group at 54.8 percent.
Also, a cardiac biomarker (N-terminal pro-brain natriuretic peptide level) did not differ between the two groups.
Researchers recorded major heart episodes in six metformin patients (3.1 percent) and two placebo patients (1.1 percent).
Based on these results, the authors concluded that “it is unlikely that metformin will have a significant effect on long-term outcome after STEMI in patients without diabetes.”
“The present findings do not support the use of metformin in this setting,” they wrote.
The study was published online March 31 in JAMA, corresponding with a presentation at the 2014 American College of Cardiology Scientific Sessions.