Out-of-Hospital Cardiac Arrest Characteristics, Care Processes, and Outcomes Across the Urban-Rural Spectrum: A Retrospective Cohort Study from 2013-2019 in the United States

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Grubic, Nicholas
Out-of-hospital cardiac arrest , Cardiopulmonary resuscitation , Automated external defibrillator , Urban-rural spectrum
BACKGROUND: Despite regional variation in survival after out-of-hospital cardiac arrest (OHCA), few studies have investigated urban-rural differences in care and outcomes. This study evaluated the impact of bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use on survival after OHCA across the urban-rural spectrum. METHODS: This was a retrospective cohort study of adult, non-traumatic, and treated OHCAs registered in the Cardiac Arrest Registry to Enhance Survival from 2013 to 2019. The geographical status of arrest locations was classified as urban, suburban, large rural, small town, or rural, according to the United States Rural-Urban Commuting Area (RUCA) classification system. Bystander interventions were categorized into no bystander intervention, bystander CPR alone, and bystander AED use. The primary outcome of interest was survival to hospital discharge with good neurological outcome. Multivariable logistic regression was used to assess the association between bystander interventions and survival by geographical status, adjusting for known confounding variables. RESULTS: A total of 325,477 OHCA patients were included in this study. Bystander CPR alone occurred most often in rural areas (50.8%), and least often in urban areas (35.4%). The proportion of patients receiving bystander AED use varied across the urban-rural spectrum (1.7%-2.9%). Survival with good neurological outcome varied for urban (8.1%), suburban (7.7%), large rural (9.1%), small town (7.1%), and rural areas (6.1%). In comparison to no bystander intervention, the adjusted odds ratios (95% confidence intervals) for bystander AED use and survival were 2.57 (2.37-2.79) in urban areas, 2.58 (1.81-3.67) in suburban areas, 1.99 (1.44-2.76) in large rural areas, 1.90 (1.27-2.86) in small towns, and 3.05 (1.99-4.68) in rural areas. Bystander CPR alone was also associated with survival in all areas (urban: 1.36 [1.31-1.41], suburban: 1.29 [1.12-1.49], large rural: 1.40 [1.20-1.63], small town: 1.32 [1.11-1.58], rural: 1.45 [1.17-1.81]). There was no strong evidence of interaction between bystander interventions and geographical status on the primary outcome (p=0.63). CONCLUSIONS: Bystander CPR and AED use are associated with positive clinical outcomes after OHCA in all areas along the urban-rural spectrum. There was no strong evidence to suggest that the survival impact of these interventions depended on the geographical status of arrest locations.
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