Certain infusion therapy after heart attack does not appear to be beneficial, may cause harm

Infusion of a combination therapy consisting of glucose, insulin, and potassium, which was thought could be a beneficial treatment immediately following a heart attack, may increase the risk of heart failure and death in the first 3 days for patients with ST-segment elevation myocardial infarction (STEMI; a certain pattern on an electrocardiogram following a heart attack), according to a study in the November 28 issue of JAMA.

Small studies have supported the use of glucose-insulin-potassium (GIK) infusion in the treatment of STEMI, while a larger study indicated a neutral effect of GIK infusion on the risk of death at 30 days after a heart attack, according to background information in the article.

Rafael Díaz, M.D., of the Etudios Cardiologica Latin America, Rosario, Argentina, and Abhinav Goyal, M.D., M.H.S., from the Emory School of Medicine, Atlanta, and colleagues conducted a study to determine the association between GIK infusion therapy and 30-day and 6-month outcomes in patients with STEMI, and whether GIK infusion may cause harm in the early post-infusion period. The study included analysis of the outcomes of the OASIS-6 GIK randomized controlled trial of 2,748 patients with acute STEMI, and the prespecified analyses of the combined trial data from the OASIS-6 GIK and CREATE-ECLA GIK trial populations of 22,943 patients with acute STEMI.

The researchers found that in the OASIS-6 trial, there were no differences between the GIK infusion and control groups in the 30-day outcomes of death, heart failure, or the composite of death or heart failure. There also were no differences in six-month clinical event rates

In the combined OASIS-6 and CREATE-ECLA GIK trial results, there were no differences between the GIK infusion and control groups in the 30-day rate of death, heart failure, or the composite of death or heart failure. In the analyses from days 0 to 3, the risks of death and the composite of death or heart failure were higher in the GIK group compared with the control group, with 712 deaths (6.2 percent) in the GIK group and 632 deaths (5.5 percent) in the control group; and 1,509 death or heart failure events in GIK group (15.8 percent) and 1,388 events in the control group (14.5 percent). The difference in the death rate disappeared by 30 days, with 1,108 deaths (9.7 percent) in the GIK group and 1,068 (9.3 percent) in the control group.

“GIK therapy increased levels of glucose, potassium, and net fluid gain post-infusion, all three of which predicted death after adjusting for multiple confounders. Adjusting for glucose, potassium, and net fluid gain eliminated the apparent increase in mortality at 3 days observed with GIK infusion, suggesting a direct association with these factors. Administration of GIK infusion within 4 hours of symptom onset yielded no benefit compared with later initiation,” the authors write.

“The combined OASIS-6 and CREATE-ECLA trial analysis of almost 23,000 patients with STEMI (the largest global experience with GIK therapy) demonstrates that GIK infusion has no effect on any important clinical end point through 30 days following STEMI. However, contrary to our prespecified hypothesis, we observed a higher rate of death and the composite of death or heart failure at 3 days in patients allocated to GIK therapy compared with control.”