Abstract Sat303: Association of Metformin Use with Survival from Cardiac Arrest in the Emergency Department

Background: Metformin, an anti-diabetic oral medication with anti-inflammatory properties, has been shown in animal models to protect against ischemia-reperfusion injury post Cardiac Arrest (CA). There is a paucity of data on the survival outcomes of Emergency Department (ED) patients with metformin use. Research Question: Our objective was to investigate the association of CA outcomes in ED patients with reported history of metformin use prior to CA. Aims: We sought to determine the association of history of metformin use prior to CA in the ED with survival to admission, hospital discharge, and neurological function. Hypothesis: Metformin use prior to ED CA is associated with increased odds of survival to admission, hospital discharge, and improved neurological function. Methods: This is a single-center, registry-based, retrospective cohort study of adult, non-traumatic CA patients seen in our quaternary care ED from 1/3/2017 to 8/25/2024. Patients with existing do not resuscitate orders were excluded. Outside hospital cardiac arrest (OHCA) as well as in ED CA patients were included. Patient demographics, history of diabetes mellitus (DM) and metformin use, pre-hospital and/or ED initial rhythms, survival to admission and hospital discharge, and neurologic function on modified Rankin Scale (mRS) were collected and entered into the registry. Descriptive statistics, bivariate tests and multivariable regression analysis were used. Results: 744 CA patients were included. Median age was 76 years (IQR: 63-86), 59.3% male, 55.1% White, and 75.5% OHCA. Initial prehospital shockable rhythm in OHCA was 16.6%. ED shockable rhythm was 13.9%. Overall, 34.4% had DM history and 68 (9.1%) had history of metformin use, which was associated with increased survival to admission (54% vs 41%, p=0.03) and survival to discharge (23% vs 12%, p=0.01) compared to no metformin use (table 1). When controlling for age and initial rhythm, there was no significant difference in survival to hospital admission; however, survival to hospital discharge was higher with metformin use (OR 2.68; 95% CI 1.13-6.34; table 2). mRS were comparable. Conclusion: Metformin use prior to OHCA and ED CA is associated with higher odds of survival to hospital discharge, but no difference in survival to hospital admission when controlling for age and initial rhythm.