title: Interaction effects between highly-educated neighborhoods and dispatcher-provided instructions on provision of bystander cardiopulmonary resuscitation.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: sy2376@hanmail.net.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea. Electronic address: Ro.youngsun@gmail.com.
authors.forename: Young Sun
authors.initials: YS
authors.lastname: Ro
authors.affiliation: Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: shinsangdo@medimail.co.kr.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Shin
authors.affiliation: Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address: skciva@gmail.com.
authors.forename: Kyoung Jun
authors.initials: KJ
authors.lastname: Song
authors.affiliation: Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea. Electronic address: arendt75@gmail.com.
authors.forename: Ki Ok
authors.initials: KO
authors.lastname: Ahn
authors.affiliation: Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea. Electronic address: minkim229@gmail.com.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Korea Centers for Disease Control and Prevention, Osong, Republic of Korea. Electronic address: soh822@hanmail.net.
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Hong
authors.affiliation: Korea Centers for Disease Control and Prevention, Osong, Republic of Korea. Electronic address: ruyoung@cdc.go.kr.
authors.forename: Young Taek
authors.initials: YT
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation; D003430:Cross-Sectional Studies; D004522:Educational Status; D000071822:Emergency Medical Dispatcher; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D012111:Residence Characteristics; D055815:Young Adult
keywords: Cardiopulmonary resuscitation; Community; Education; Out-of-hospital cardiac arrest