Type 2 diabetes drug metformin associated with lower risk of heart disease and all cause mortality
Not only is metformin the oldest diabetes drug, it is also still the first choice for diabetes treatment. Researchers wanted to see if metformin still remains a good choice. These researchers found Type 2 diabetes patients taking metformin may have a lower risk of heart disease and death, compared to patients on insulin.
These findings suggest that metformin has a lower risk of side effects than other common diabetes drugs.
Patients taking metformin also had a slightly lower risk of death compared to patients taking oral hypoglycemic agents (drugs used to control blood sugar levels).
Metformin was first created and found to lower blood sugar levels in the 1920s. Almost a century later, it is still a first-line treatment for type 2 diabetes.
Dr. Nils Ekström, of the University of Gothenburg in Sweden, and colleagues set out to study the safety and effectiveness of metformin in a large group of men and women with type 2 diabetes.
On top of finding that patients taking metformin had a lower risk of heart disease and death, the researchers found that patients with weakened kidney function did not have an increased risk of heart disease, death or serious infection.
Other findings showed that metformin, compared to any other treatment, was associated with a lower risk of acidosis (too much acid in the body fluids) and serious infection among patients with an estimated Glomerular Filtration Rate, or eGFR (a measure of kidney function), of 45 to 60.
Among patients with an eGFR of 30 to 45, metformin had no increased risk of all-cause mortality, acidosis, serious infection or heart disease.
An eGFR of 60 and above is considered normal. Kidney disease is marked by an eGFR below 60. Kidney failure is marked by an eGFR of 15 or below.
Metformin was also associated with a lower all-cause mortality (risk of death from all causes).
They also found that:
- patients taking oral hypoglycemic agents had a hazard ratio of 1.02 for heart disease
- patients taking oral hypoglycemic agents had a hazard ratio of 1.13 for all-cause mortality
- patients taking insulin had a hazard ratio of 1.18 for heart disease
- patients taking insulin had a hazard ratio of 1.34 for all-cause mortality
A hazard ratio is a measure of how often one event happens in one group versus how often it happens in another group over a period of time. A hazard ratio of more than one means that the particular event happens more in one group than the other.
”In clinical practice, the benefits of metformin use clearly outbalance the risk of sever side effects,” the authors said.
This study – which included more than 51,000 patients with type 2 diabetes – was published July 13 in BMJ Open.
Abstract
Objective To evaluate the effectiveness and safety of metformin use in clinical practice in a large sample of pharmacologically treated patients with type 2 diabetes and different levels of renal function.
Design Observational study between July 2004 and December 2010, mean follow-up 3.9 years.
Setting Hospital outpatient clinics and primary care in Sweden.
Participants 51 675 men and women with type 2 diabetes, registered in the Swedish National Diabetes Register, and on continuous glucose-lowering treatment with oral hypoglycaemic agents (OHAs) or insulin.
Main outcome measures Risks of cardiovascular disease (CVD), all-cause mortality and acidosis/serious infection, associated with each treatment regimens, were analysed in all patients and in subgroups with different estimated glomerular filtration rate (eGFR) intervals. Covariance adjustment and propensity scores were used to adjust for several baseline risk factors and characteristics at Cox regression.
Results Compared with metformin in monotherapy, HRs for fatal/non-fatal CVD and all-cause mortality with all other OHAs combined (approximately 80% sulphonylureas) in monotherapy were 1.02 (95% CI 0.93 to 1.12) and 1.13 (1.01 to 1.27), while 1.18 (1.07 to 1.29) and 1.34 (1.19 to 1.50) with insulin in monotherapy, adjusting using propensity scores. Metformin, compared with any other treatment, showed reduced risks of acidosis/serious infection (adjusted HR 0.85, 95% CI 0.74 to 0.97) and all-cause mortality (HR 0.87, 95% CI 0.77 to 0.99), in patients with eGFR 45–60 ml/min/1.73 m2, and no increased risks of all-cause mortality, acidosis/serious infection or CVD were found in patients with eGFR 30–45 ml/min/1.73 m2.
Conclusions Metformin showed lower risk than insulin for CVD and all-cause mortality and slightly lower risk for all-cause mortality compared with other OHA, in these 51 675 patients followed for 4 years. Patients with renal impairment showed no increased risk of CVD, all-cause mortality or acidosis/serious infection. In clinical practice, the benefits of metformin use clearly outbalance the risk of severe side effects.
