Association of serum calcium levels with cardiac arrest risk in heart failure patients from the eICU database

Sudden cardiac arrest (SCA) is a critical condition with high mortality, particularly in patients with heart failure. Serum calcium levels play a crucial role in cardiac electrophysiology, but their association with SCA in heart failure patients remains unclear. This study aimed to investigate the relationship between serum calcium levels and the risk of SCA in heart failure patients using data from the eICU Collaborative Research Database (eICU-CRD).We conducted a retrospective cohort study of 11,373 heart failure patients admitted to intensive care units (ICUs) across the United States between 2014 and 2015. Serum calcium levels were measured upon ICU admission, and the primary outcome was in-hospital SCA. We used multivariable logistic regression and generalized additive models (GAM) to explore the dose-response relationship between serum calcium levels and SCA risk. This study reveals a significant non-linear relationship between serum calcium levels and the risk of in-hospital SCA in ICU patients with heart failure. The results indicate that for every 1 mg/dL increase in serum calcium, the risk of SCA decreases, with a notable reduction in risk (OR = 0.62) when serum calcium levels are below 9.5 mg/dL, while the risk significantly increases (OR = 2.73) when levels exceed this threshold. And similar conclusions were repeatedly obtained in the sensitivity analysis using albumin-corrected calcium values.