Insulin Use as a Secondary Treatment for Type 2 Diabetes Linked to Heart Disease, Death

Patients with type 2 diabetes who take a combination of metformin plus insulin may be at higher risk for cardiovascular disease and death compared with those who take a combination of metformin plus sulfonylurea, according to a new AHRQ-funded study in the June 11 issue of the Journal of the American Medical Association (JAMA). The study, a review of medical records from national databases, found a greater association between insulin as a second-line treatment and risk of death and cardiovascular disease than sulfonylureas as second-line treatment. In the new study, AHRQ-funded researchers led by Christianne L. Roumie, M.D., M.P.H., of the Tennessee Valley Veterans Affairs Medical Center in Nashville, analyzed records from databases at the Veterans Health Administration (VHA), Centers for Medicare & Medicaid Services and the National Center for Health Statistics. They studied more than 42,000 patient records and the National Death Index to assess the effects of insulin and sulfonylureas, the two medications most commonly prescribed in the study population as second-line treatment for diabetes. The retrospective cohort study compared 2,500 VHA patients who added insulin to their metformin regimen with 12,000 VHA patients who added a sulfonylurea. On average, patients were about 60 years old, and about 35 percent had history of heart disease or stroke. The patients studied had been on metformin for an average of 14 months, and their average hemoglobin A1c count (a key indicator of success in controlling blood sugar) was 8.1 percent, which is higher than is preferred, when the second medication was prescribed. The researchers identified patients who were taking one of two drug combinations: metformin-plus-insulin or metformin-plus-sulfonylurea. Then they compared the risks of heart attack, stroke or death for these patients. They found an association of metformin-plus-insulin to have a higher risk of cardiovascular events and death than metformin-plus-sulfonylureas, although harms were found for both regimens. Please access AHRQ’s press release for more information.