High Glucose Levels Associated With Worse Outcomes After Acute Myocardial Infarction

Variations in glucose levels can help indicate the severity of an acute myocardial infarction regardless of whether the individual has diabetes, with higher levels being associated with a worsened outcome, larger infarction, and greater reduction in left ventricular ejection fraction (LVEF), according to the results of a study based in Brazil and published in Diabetology and Metabolic Syndrome.¹

“The findings surprised us, and based on our literature review, they were unprecedented,” Henrique Tria Bianco, professor at the Federal University of São Paulo (UNIFESP) and corresponding author, said in an accompanying news release. “They open a number of doors for us to further study the pathophysiology of patients who have had a myocardial infarction.”²

Myocardial infarction can be exacerbated by high glucose levels. | Image Credit: © dragonstock - stock.adobe.com

Relation Between Myocardial Infarction and Glucose Levels

In Brazil, acute myocardial infarction is the leading cause of death, with an estimated 300,000 to 400,000 cases annually. Myocardial infarction, known as a heart attack, occurs when the clotting of heart muscles causes cell death, severely interrupting blood flow. Chest pain or discomfort is the hallmark symptom, accompanied by tightness and intense, prolonged pain.²

Separately, hyperglycemia, which is most often seen in patients with diabetes, is associated with poor clinical outcomes in numerous clinical scenarios. Stress hyperglycemia (SH) differs in that it is characterized by a transient rise in blood glucose during acute physiological stress. Research has affirmed the role that stress hyperglycemia can play in contributing to inflammatory responses and adverse outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Furthermore, SH is closely related to acute myocardial infarction, regardless of the presence of diabetes; together, they are linked to a heightened incidence of nephropathy, cardiogenic shock, and mortality.^3,4

Increased Glycemic Delta Worsens Outcomes in Myocardial Infarction

Using a pharmacoinvasive strategy, the current authors sought to examine the association between SH and cardiac outcomes in patients with STEMI. Glucose data was used to quantify glycemic dysregulation, while cardiac magnetic resonance (CMR) imaging helped assess infarct size and LVEF. Patients aged 18 years or older diagnosed with STEMI who were treated with fibrinolysis—medication designed to dissolve the infarction-causing clot—were enrolled in the study. The patients were first treated at units throughout Brazil’s hospital network specializing in fibrinolysis; next, they were transferred to Hospital São Paulo.^1,2

A total of 244 patients with STEMI were enrolled. Findings from CMR imaging found a positive correlation between glucose delta—obtained by calculating the admission blood glucose level minus the estimated average blood glucose level in previous months—and fibrosis percentage. Simultaneously, there was a negative correlation between glucose data and LVEF, indicating that higher glucose delta values are associated with increased fibrosis and impaired LVEF. A linear regression analysis showed a similar finding, demonstrating a significant association between glucose delta and reduced LVEF (–0.05 [95% CI, –0.04 to –0.02]; P = .04). Glucose delta was also positively associated with greater infarct size, highlighting the association between heightened glucose levels and severity 30 days post-MI.^1,2

In their discussion, the investigators noted that SH is driven by the body’s stress response, increasing production of cortisol and adrenaline, heightening blood sugar, and exacerbating heart injury. When a myocardial infarction occurs, SH—through oxidative pressure and increased inflammation—can worsen outcomes. The results of this trial indicate that glycemic data, specifically glucose delta, can be tracked for fluctuations that could serve as indicators of cardiac damage. This occurred regardless of diabetes status, emphasizing that increased glucose level tracking should be employed in patients with and without diabetes.¹

“Through a simple, inexpensive test that almost all patients do, which is glycated hemoglobin for hospital admission, we end up with an easy-to-obtain biomarker with important implications,” Francisco Antonio Fonseca, UNIFESP professor, explained in the news release. “In other words, patients with a higher delta will have greater infarct mass and will need myocardial protection, both in relation to blood glucose and, for example, the use of beta-blockers, to improve their prognosis.”¹

Pharmacists are growing increasingly essential in glucose monitoring and are in a prime position to counsel patients as to the importance of keeping track of their glucose levels. Tools such as continuous glucose monitors could be recommended for patients at highest risk. Furthermore, if a patient is at known risk of myocardial infarction, a pharmacist can encourage them to report for more frequent checkups to ensure their glucose levels remain level.¹

REFERENCES

1. Garcia BF, Fonseca FA, Izar MC, et al. Impact of elevated glucose levels on cardiac function in STEMI patients: glucose delta as a prognostic biomarker. Diabetology & Metabolic Syndrome. 2025;17:203. doi:10.1186/s13098-025-01738-0

2. Fundação de Amparo à Pesquisa do Estado de São Paulo. Variations in glucose levels may indicate severity of heart attack damage. EurekAlert!. News Release. Released September 4, 2025. Accessed September 16, 2025. https://www.eurekalert.org/news-releases/1097123

3. Cassarotti ACA, Teixeira D, Longo-Maugeri IM, et al. Role of B lymphocytes in the infarcted mass in patients with acute myocardial infarction. Bioscience Reports. 2021;41(2):BSR20203413. doi:10.1042/BSR20203413

4. Khalfallah M, Abdelmageed R, Hafez YM, et al. Incidence, predictors and outcomes of stress hyperglycemia in patients with ST elevation myocardial infarction undergoing primary percutaneous coronary intervention. Diabetes & Vascular Disease Research. 2019;17(1). doi:10.1177/1479164119883983