Prognostic implications of glucose-lowering treatment in patients with acute myocardial infarction and diabetes: experiences from an extended follow-up of the Diabetes Mellitus Insulin-Glucose Infusion in Acute Myocardial Infarction (DIGAMI) 2 Study

This post hoc analysis from the Diabetes Mellitus Insulin-Glucose Infusion in Acute Myocardial Infarction (DIGAMI) 2 trial reports on extended long-term outcome in relation to glucose-lowering agents in patients with myocardial infarction and type 2 diabetes. Patients were randomised as follows: group 1, insulin-based treatment; group 2, insulin during hospitalisation followed by conventional glucose control; and group 3, conventional treatment. Treatment according to the above protocol lasted 2.1 years. Using the total DIGAMI 2 cohort as an epidemiological database, this study presents mortality rates in the randomised groups, and mortality and morbidity rates by glucose-lowering treatment during an extended period of follow-up (median 4.1 and max 8.1 years). Follow-up data were available in 1,145 of the 1,253 patients. The mortality rate was 31% (72% cardiovascular) without significant differences between treatment groups. The total number of fatal malignancies was 37, with a trend towards a higher risk in group 1. The HR for death from malignant disease, compared with group 2, was 1.77 (95% CI 0.87-3.61; p = 0.11) and 3.60 (95% CI 1.24-10.50; p = 0.02) compared with group 3. Insulin treatment was associated with non-fatal cardiovascular events (OR 1.89 95% CI 1.35-2.63; p = 0.0002), but not with mortality (OR 1.30, 95% CI 0.93-1.81; p = 0.13). Metformin was associated with a lower mortality rate (HR 0.65, 95% CI 0.47-0.90; p = 0.01) and a lower risk of death from malignancies (HR 0.25, 95% CI 0.08-0.83; p = 0.02). Patients with type 2 diabetes and myocardial infarction have a poor prognosis. Glucose-lowering drugs appear to be of prognostic importance. Insulin may be associated with an increased risk of non-fatal cardiac events, while metformin seems to be protective against risk of death.