Interaction effects between highly-educated neighborhoods and dispatcher-provided instructions on provision of bystander cardiopulmonary resuscitation

Background: Socioeconomic factors of a community are associated with bystander cardiopulmonary resuscitation (BCPR) rates and outcomes of out-of-hospital cardiac arrest (OHCA). This study aimed to test whether dispatcher-provided CPR instruction modifies the association between education level of a community and provision of BCPR.

Methods: A population-based observational study was conducted with OHCAs of cardiac etiology who were witnessed by laypersons between 2012 and 2013. Exposure variable was the proportion of highly-educated residents (high school graduates and higher) in a community categorized into quartile groups. Endpoints were provision of BCPR and early chest compression (≤4min of collapse, ECC). Multivariable logistic regression analysis was performed. A final model with an interaction term was evaluated to test interactive effects of community education level with dispatcher-provided CPR instruction.

Results: A total of 10,694 OHCAs were analyzed. BCPR was performed in 5112 (47.8%), and early CPR was done in 3080 (28.8%). Compared with the highest educated communities, AORs (95%CIs) for BCPR were 0.84 (0.74-0.95) in higher, 0.78 (0.66-0.92) in lower, and 0.71 (0.60-0.85) in the lowest educated communities. For ECC, AORs (95%CIs) were 0.81 (0.66-0.99) in lower and 0.62 (0.50-0.76) in the lowest. In an interaction model of 4122 OHCA patients who received dispatcher-provided CPR instruction, OHCAs occurring in higher (AOR: 0.80 (0.67-0.96)), lower (AOR: 0.67 (0.52-0.87)), and the lowest (AOR: 0.59 (0.43-0.82)) were less likely to receive BCPR compared with the highest educated communities.

Conclusion: OHCA patients in communities with a higher proportion of highly-educated residents were more likely to receive BCPR, and the disparity was more prominent in the group that received dispatcher-provided CPR instruction.