Insulin-Metformin Combined Therapy tied to Increased Mortality Rates for Diabetics
New research out of Vanderbilt University found that Type 2 diabetics who took a combination of metformin and insulin had a slightly increased risk of dying in comparison to other diabetics who did not mix the two types of medications.
For this study, the researchers examined data on more than 178,000 patients taking metformin provided by the U.S. Veterans Health Administration (VA), Medicare and the National Death Index. Nearly 3,000 patients had added insulin and around 40,000 added a sulfonylurea, which is a type of drug that stimulates the body to produce more insulin.
After focusing on around 2,400 people taking insulin-metformin and 12,000 people on sulfonylurea-metformin, the researchers found very small differences in the incidence rates for heart attacks and strokes. However, the researchers did find that patients taking insulin-metformin had a higher mortality rate.
"Insulin remains a reasonable option for patients who have very high glucose [blood sugar] or who desire flexible and fast blood sugar control, but most patients taking metformin prefer to delay starting insulin," said lead researcher Dr. Christianne Roumie, an associate professor of internal medicine and pediatrics at Vanderbilt University in Nashville, TN. "The current study suggests that adding a sulfonylurea to metformin should be preferred to adding insulin for most patients who need a second diabetes drug."
Experts were quick to criticize the study, stating that the researchers did not account for how sick the patients were when they compared the results. For example, patients who are sicker will have a higher death risk.
"We have a number of studies planned to examine possible mechanisms. We are investigating type 2 diabetes outcomes associated with blood sugar swings and with episodes of hypoglycemia [low blood sugar] tied to insulin," Roumie stated according to WebMD.
The study was published in the Journal of the American Medical Association.