Association between metformin and survival outcomes in in-hospital cardiac arrest patients with diabetes

Introduction: Metformin has shown cardioprotective and neuroprotective effects in cardiac arrest and ischemia-reperfusion injury animal models. Therefore, this study aimed to determine the association between diabetes medication and survival outcomes in in-hospital cardiac arrest (IHCA) patients with type 2 DM (T2DM). Methods: This retrospective observational study included adult IHCA patients with T2DM between April 2017 and March 2022. The variable of interest was administration of diabetes medications within 24 h before cardiac arrest. Multivariable logistic regression analysis was performed. Results: In the 377 included patients, administration of metformin within 24 h before IHCA was associated with a higher rate of survival to discharge and good neurologic outcome (41.5% vs 11.7%, P < 0.001 and 18.9% vs 6.2%, P = 0.004, respectively). Administration of metformin within 24 h before IHCA was independently associated with survival to discharge and good neurologic outcome (aOR: 5.37, 95% CI: 2.13–13.53, P < 0.001 and aOR: 3.57, 95% CI: 1.14–11.17, P = 0.029). The rate of survival to discharge was the highest in patients who were administered 500–1000 mg/day metformin (P < 0.001). Conclusions: In IHCA patients with T2DM, administration of metformin within 24 h before IHCA was independently associated with survival to discharge.