Abstract Body (Do not enter title and authors here): Introduction: Risk stratifying diabetes mellitus (DM) patients with chest pain in the emergency department (ED) can pose significant challenges because of atypical symptoms, non-specific ECG changes, and elevated baseline troponin levels. This study aims to evaluate HEART Score performance in DM versus non-DM patients.

Methods: A prospective observational cohort study included chest pain patients transported by Emergency Medical Services to University of Pittsburgh Medical Center-affiliated hospitals. Data collection involved extracting data from electronic health records, including both DM and non-DM patients with chest pain. The HEART Score was retrospectively calculated by impartial assessors.The primary endpoint was major adverse cardiac events (MACE) within 30 days. This analysis included the classification performance of bivariate comparisons between the HEART Score and ACS outcomes using the area under the receiver-operator characteristic curve (AUC).

Results: 4,058 patients were included. 52.7% were male, 42% were white, there was a mean age of 59.24 years (16.13 SD), 28.63% had DM, and 22.1% had MACE. MACE prevalence was 19.7% in non-DM patients and 28% in patients with DM. The AUC demonstrated more robust discriminatory ability of the HEART Score in non-DM (AUC = 0.81) (95% CI 0.79-0.83) versus DM patients (AUC = 0.74) (95% CI 0.71-0.78) (p 0.001). The performance of HEART Score components, including history, age, and risk factors, exhibited better significant predictive capability for MACE in non-DM patients compared to DM patients. Conversely, the HEART-ECG and troponin components were not different between the DM and non-DM groups. The HEART Score demonstrates better performance in White individuals and females when contrasted with males and Black individuals. Nevertheless, these disparities do not reach statistical significance.

Conclusion: The HEART Score performs differently in DM versus non-DM patients, with stronger discrimination observed in non-DM individuals. The troponin and ECG components exhibit poorer performance in diabetes mellitus (DM) patients within the context of the HEART Score. This underscores the complexity of risk assessment in DM patients with chest pain and suggests the necessity for further exploration and refinement of risk stratification strategies in this population.