Identification of High-Risk Communities for Unattended Out-of-Hospital Cardiac Arrests Using GIS

Improving survival rates for out of hospital cardiac arrest (OHCA) at the neighborhood level is increasingly seen as priority
in US cities. Since wide disparities exist in OHCA rates at the neighborhood level, it is necessary to locate neighborhoods
where people are at elevated risk for cardiac arrest and target these for educational outreach and other mitigation strategies.
This paper describes a GIS-based methodology that was used to identify communities with high risk for cardiac arrests in Franklin
County, Ohio during the period 2004–2009. Prior work in this area used a single criterion, i.e., the density of OHCA events,
to define the high-risk areas, and a single analytical technique, i.e., kernel density analysis, to identify the high-risk
communities. In this paper, two criteria are used to identify the high-risk communities, the rate of OHCA incidents and the
level of bystander CPR participation. We also used Local Moran’s I combined with traditional map overlay techniques to add
robustness to the methodology for identifying high-risk communities for OHCA. Based on the criteria established for this study,
we successfully identified several communities that were at higher risk for OHCA than neighboring communities. These communities
had incidence rates of OHCA that were significantly higher than neighboring communities and bystander rates that were significantly
lower than neighboring communities. Other risk factors for OHCA were also high in the selected communities. The methodology
employed in this study provides for a measurement conceptualization of OHCA clusters that is much broader than what has been
previously offered. It is also statistically reliable and can be easily executed using a GIS.