The present study prospectively investigated the effect of blood glucose level at admission on monocyte chemoattractant protein-1 levels at different time points before and after primary percutaneous coronary intervention, and the postoperative 1-year prognosis of patients with acute ST-segment elevation myocardial infarction. The 146 patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention were divided into three groups: Group 1, non-diabetic, non-hyperglycemic group; group 2, stress hyperglycemia group; and group 3, diabetic group. Serum monocyte chemoattractant protein-1 levels before and after percutaneous coronary intervention (PCI), and the incidence of major adverse cardiovascular events 1-year post PCI were observed. The increase in monocyte chemoattractant protein-1 levels 24 h after percutaneous coronary intervention, compared with those before percutaneous coronary intervention, was significantly correlated with the blood glucose level at admission. Furthermore, the 1-year postoperative major adverse cardiovascular events rates were significantly higher in groups 2 and 3 compared with group 1. Logistic regression analysis demonstrated that a high blood glucose level at admission, diabetes, and high preoperative monocyte chemoattractant protein-1 levels were risk factors for major adverse cardiovascular events 1-year post-percutaneous coronary intervention. Stress hyperglycemia and diabetes may contribute to high monocyte chemoattractant protein-1 levels and prolonged inflammation. These symptoms are associated with poor prognosis of acute ST-segment elevation myocardial infarction in patients undergoing primary percutaneous coronary intervention.