title: Geographic factors are associated with increased risk for out-of hospital cardiac arrests and provision of bystander cardio-pulmonary resuscitation in Singapore.
abstract: BACKGROUND
  Bystander Cardio-Pulmonary Resuscitation (BCPR) can improve survival for Out-of-Hospital Cardiac Arrest (OHCA). This study aimed to investigate the geographic variation of BCPR provision and survival to discharge outcomes among residential OHCA cases, evaluate this variation with individual and population characteristics and identify high-risk residential areas with low relative risk (RR) of BCPR and high RR of OHCA at the development guide plan (DGP) census tract levels in Singapore.
  
  
  METHODS
  This was a retrospective, secondary analysis of two prospectively-collected registries in Singapore from 2001 to 2011. We used Bayesian conditional autoregressive spatial models to examine predictors at the DGP level and calculate smoothed RR to identify high-risk areas. We used multi-level mixed-effects logistic regression models to examine the independent effects of individual and neighborhood factors.
  
  
  RESULTS
  We found a total of 3942 OHCA with a BCPR rate of 20.3% and a survival to discharge rate of 1.9% and 3578 cases eligible for BCPR. After adjusting for age, witnessed status, presumed cardiac etiology and longer response time, the risk of BCPR provision significantly increased by 0.02% for every 1% increase in the proportion of household size 5 and above in the DGP area (odds ratio 1.02, 95%CI=1.002-1.038, p<0.026). We identified 10 high-risk residential areas with low RR of BCPR and high RR of OHCA.
  
  
  CONCLUSIONS
  This study informed that neighborhood household size could have played a significant role in the provision of BCPR and occurrence of high-risk areas. It demonstrates the public health potential of combining geospatial and epidemiological analysis for improving health.
authors: Department of Emergency Medicine, Singapore General Hospital, Singapore Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore. Electronic address: marcus.ong.e.h@sgh.com.sg.
authors: Marcus Eng Hock
authors: ME
authors: Ong
authors: Centre for Infectious Disease Epidemiology and Research, Saw Swee Hock School of Public Health, National University of Singapore, Singapore. Electronic address: win_wah@nuhs.edu.sg.
authors: Win
authors: W
authors: Wah
authors: Centre for Infectious Disease Epidemiology and Research, Saw Swee Hock School of Public Health, National University of Singapore, Singapore. Electronic address: li_yang_hsu@nuhs.edu.sg.
authors: Li Yang
authors: LY
authors: Hsu
authors: Medical Department, Singapore Civil Defence Force, Singapore. Electronic address: ng_yih_yng@scdf.gov.sg.
authors: Yih Ying
authors: YY
authors: Ng
authors: Emergency Medicine Department, National University Hospital, Singapore. Electronic address: leong_benjamin@yahoo.com.sg.
authors: Benjamin Sieu-Hon
authors: BS
authors: Leong
authors: Acute and Emergency Care Centre, Khoo Teck Puat Hospital, Singapore. Electronic address: goh.e.shaun@alexandrahealth.com.sg.
authors: E Shaun
authors: ES
authors: Goh
authors: Accident and Emergency Department, Changi General Hospital, Singapore. Electronic address: han_nee_gan@cgh.com.sg.
authors: Han Nee
authors: HN
authors: Gan
authors: Children's Emergency, KK Women's and Children's Hospital, Singapore. Electronic address: tham.lai.peng@kkh.com.sg.
authors: Lai Peng
authors: LP
authors: Tham
authors: Emergency Medicine Department, Alexandra Hospital, Singapore. Electronic address: charles_rabind@juronghealth.com.sg.
authors: Rabind Antony
authors: RA
authors: Charles
authors: Department of Cardiology, Tan Tock Seng Hospital, Singapore. Electronic address: david_foo@ttsh.com.sg.
authors: David Chee Guan
authors: DC
authors: Foo
authors: Centre for Quantitative Medicine, Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore. Electronic address: arul.earnest@duke-nus.edu.sg.
authors: Arul
authors: A
authors: Earnest
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation; D005260:Female; D005843:Geography; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000453:epidemiology* / Q000628:therapy*; D012111:Residence Characteristics; D012189:Retrospective Studies; D012307:Risk Factors; D012846:Singapore
keywords: Cardiopulmonary resuscitation; Epidemiology; Out-of-hospital cardiac arrest; Prehospital emergency care; Spatial analysis