(RxWiki News) For years, it was thought that long-term use of insulin caused heart disease in diabetes patients. Now, it looks like that belief may no longer hold weight.
Long-term insulin use may not increase the risk of heart attacks, stroke, or cancer in people with diabetes or pre-diabetes.
"Ask your doctor about the risks of your diabetes treatment."
Doctors and researchers have been concerned for some time that long-term use of insulin may lead to heart disease, explains Hertzel Gerstein, MD, of McMaster University and principal investigator of the current study.
Dr. Gerstein and his fellow researchers set out to put this concern to the test in their ORIGIN study (Outcome Reduction with an Initial Glargine Intervention study).
They recruited more than 12,500 people with type 2 diabetes or pre-diabetes, a condition in which blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes. The participants were separated into two groups: one that received one daily injection of insulin for six years and one that received no insulin.
The risk of heart disease and other heart-related events was the same for both groups. There also was no difference in cancer risk between the two groups.
These findings suggest long-term daily use of insulin is not harmful.
"People have been debating the question of whether there are adverse consequences to long-term insulin use for years," says Dr. Gerstein.
"This study provides the clearest answer yet to that question: No, there are not," he says.
During their study, the researchers observed hypoglycemia (low blood sugar) and weight gain - two common side effects of insulin use. However, these side effects were minor and not harmful.
"We now know what the risks are of taking insulin on a long-term basis, and they are low," says Dr. Gerstein.
Results from the study also show that pre-diabetes patients who received daily insulin injections had a 28 percent lower risk of type 2 diabetes, even after they stopped taking insulin.
Furthermore, taking a daily dose of one-gram omega-3 fatty acid supplements did not prevent heart-related deaths in people with type 2 diabetes or pre-diabetes.
According to Jackie Bosch, of McMaster University's School of Rehabilitation Science and project manager of the study, "There was neither benefit nor harm in the participants who were studied.
"However, the effect of these supplements in other groups, and the effect of a diet rich in omega-3 fatty acids, was not studied," says Bosch.
This research was funded by Sanofi Inc., a drug manufacturer.
It is published in two papers in the New England Journal of Medicine.