Age-Dependent Geographic Convergence of Overdose and Cardiovascular Emergency Medical Services Calls: A Spatial Point Process Analysis

Introduction: Overdose and cardiovascular disease are both leading causes of emergency medical services (EMS) activation. The objective of this study was to identify differential patterns in cardiac EMS activations by age and explore whether suspected overdose activity influenced these differences. Methods: EMS activations data were obtained using emsCharts software for Washington County, Pennsylvania, from 2017 through 2023. Poisson point process model (PPM) regression analyses were conducted to estimate the cardiac EMS activation per unit area, as a function of age and suspected overdose, adjusting for population size. Results: PPM regression analyses identified significant differences in EMS cardiac activations for people aged 18 to 45 years compared with people older than 45 years (β = -1.83, SE = 0.020, 95% CI = -1.86 to -1.79). EMS activations increased as population size increased (β = 0.21, SE = 0.001, 95% CI = 0.21 to 0.22). Analysis also identified significant differences in EMS activation per unit area for age groupings, depending on local suspected overdose activity (interaction term) (β = 0.02, SE = 0.001, 95% CI = 0.01 to 0.02). Likelihood-ratio tests indicated that using suspected overdose activity as an effect modifier on age-dependent cardiac EMS activations improved model fit (deviance = 228.12, df = 1, P < .001). Conclusions: The community-level occurrence of cardiac emergencies differs by age group, with younger adults experiencing more cardiovascular disease in neighborhoods with higher suspected overdose activity. This nuance is key to developing age-appropriate public health intervention materials to lessen early onset cardiovascular disease illness and death.