Infusion of the combination of glucose, insulin, and potassium may increase the risk of heart failure and death in the first three days for patients with ST-segment elevation myocardial infarction, according to an article in the November 28 issue of the Journal of the American Medical Association.

Small studies had supported the use of glucose-insulin-potassium infusion in the treatment of ST-elevation infarction, whereas a larger study indicated a neutral effect of infusion on the risk of death at 30 days after infarction, according to background information in the article.

Rafael Diaz, MD, of the Etudios Cardiologica Latin America, Rosario, Argentina, and Abhinav Goyal, MD, MHS, from the Emory School of Medicine, Atlanta, and colleagues conducted a study to determine the association between infusion therapy and 30-day and 6-month outcomes in patients with ST-elevation infarctions and whether infusion may cause harm in the early post-infusion period.

The study included analysis of the outcomes of the OASIS-6 randomized controlled trial of 2,748 patients with acute ST-elevation infarctions and prespecified analyses of the combined trial data from the OASIS-6 and CREATE-ECLA trial populations of 22,943 patients with acute ST-elevation infarctions.

In the OASIS-6 trial, there were no differences between 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 trial results, there were no differences between infusion and control groups in the 30-day rate of death, heart failure, or the composite of death or heart failure.

However, in the analyses from days 0 to 3, the risk of death and the composite of death or heart failure were higher in the infusion group than in the control group, with 712 deaths (6.2 percent) in the infusion group and 632 deaths (5.5 percent) in the control group and 1,509 death or heart failure events in the infusion 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 infusion 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 wrote.

"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."