Elevated Glycemic Variability Linked to AF and Mortality After AMI, suggests study

A new research published in the Journal of the National Medical Association revealed that higher glycemic variability (GV) may be associated with an increased risk of Atrial Fibrillation (AF) and mortality in patients with Acute Myocardial Infarction (AMI), even among individuals without diabetes and in White populations.

Glycemic variability may contribute to inflammation, oxidative stress, autonomic nervous system imbalance, and electrical instability in the heart, all mechanisms that could promote atrial fibrillation after myocardial infarction. This research analyzed data from 10,439 patients in the MIMIC-IV critical care database to investigate whether glycemic variability (GV) was associated with cardiovascular complications following AMI. While diabetes has long been recognized as a major cardiac risk factor, the impact of short-term glucose instability in heart attack patients has remained less clear.

The study population included both ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) cases. The median patient age was 71 years, and approximately 27% underwent invasive cardiac treatment like angioplasty or stenting. This study calculated glycemic variability using repeated plasma glucose measurements obtained after admission and the patients were then divided into quartiles according to the extent of blood sugar fluctuations.

A strong association between higher glycemic variability and the development of atrial fibrillation (AF) was observed. Overall, 16.2% of patients developed AF during hospitalization. However, incidence rates rose sharply across increasing glycemic variability levels. The patients in the highest GV quartile experienced AF at a rate of 21%, when compared with only 7.1% among those in the lowest quartile.

After adjusting for multiple clinical and demographic factors, this study found that elevated glycemic variability remained independently associated with more than double the odds of developing AF. High GV was also linked to more than twice the risk of in-hospital mortality. This association persisted even among patients without diabetes, suggesting that glucose instability itself may contribute to cardiovascular complications during acute illness.

The predictive relationship between glycemic variability and atrial fibrillation appeared particularly strong among White patients, although significant associations were also observed in non-White populations.

The findings highlight the growing importance of metabolic monitoring in critically ill cardiac patients. Overall, the findings of this study support closer glucose monitoring and future research into whether stabilizing blood sugar fluctuations could improve outcomes in AMI patients. Further prospective studies involving larger and more diverse populations are required to confirm the results.

Reference:

Liu, T., Meng, Z., Li, D., Hu, B., Sun, Y., Liu, Y., Zhang, Y., & Feng, L. (2026). The association between glycemic variability and atrial fibrillation/in-hospital mortality in white and non-white patients with acute myocardial infarction: A retrospective cohort study. Journal of the National Medical Association. https://doi.org/10.1016/j.jnma.2026.04.006