Background: The percentage of immature granulocytes (IG%) is an early marker of inflammation and has a prognostic significance in many diseases.

Objective: In this study, we tried to investigate whether the percentage of immature granulocytes has a prognostic value in 28-day mortality in patients with acute coronary syndrome (ACS).

Method: This study was carried out retrospectively between 1.1.2019 and 30.6.2019 at Mersin University Faculty of Medicine, Department of Emergency Medicine. Patients older than 18 years who applied to the emergency department with chest pain and were hospitalized with a preliminary diagnosis of ACS were included in the study. The patients were divided into two groups as survivors and non-survivors. IG% and other laboratory parameters were recorded. The relationship between IG% and 28-day mortality was analyzed. In addition, ROC analysis was performed to compare the diagnostic accuracy of IG% and other variables.

Results: A total of 617 patients, including 423 (68.6%) men, were included in the study. The mean age of the patients were 63.9 ± 12.7. IG% was higher in non-survivor patients (1.2 ± 1.4) than in surviving patients (0.5 ± 0.5) (p = 0.007). In predicting 28-day mortality, when the cut-off value for IG% was >0.6, the specifi- city was found to be 93.70% and the sensitivity to be 54.55% (AUC = 0.717, p = 0.000). In predicting 28-day mortality for ACS, IG% was an independent risk factor (hazard ratio [HR] 632.962, 95% confidence interval 3.389-118206.572, p = 0.016).

Conclusion: IG% may be associated with a 28-day mortality in patients with ACS.