Resuscitation 85 (2014) 1153–1160 Contents lists available at ScienceDirect Resuscitation j ourna l h o me pa g e : www.elsevier.com/locate/resuscitation Clinical Paper Geographic factors are associated with increased risk for out-of hospital cardiac arrests and provision of bystander cardio-pulmonary resuscitation in Singapore  Marcus Eng Hock Ong a,∗ , Win Wah b , Li Yang Hsu b , Yih Ying Ng c , Benjamin Sieu-Hon Leong d , E. Shaun Goh e , Han Nee Gan f , Lai Peng Tham g , Rabind Antony Charles h , David Chee Guan Foo i , Arul Earnest j a Department of Emergency Medicine, Singapore General Hospital, Singapore Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore b Centre for Infectious Disease Epidemiology and Research, Saw Swee Hock School of Public Health, National University of Singapore, Singapore c Medical Department, Singapore Civil Defence Force, Singapore d Emergency Medicine Department, National University Hospital, Singapore e Acute and Emergency Care Centre, Khoo Teck Puat Hospital, Singapore f Accident and Emergency Department, Changi General Hospital, Singapore g Children’s Emergency, KK Women’s and Children’s Hospital, Singapore h Emergency Medicine Department, Alexandra Hospital, Singapore i Department of Cardiology, Tan Tock Seng Hospital, Singapore j Centre for Quantitative Medicine, Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore a r t i c l e i n f o Article history: Received 4 April 2014 Received in revised form 7 May 2014 Accepted 3 June 2014 Keywords: Cardiopulmonary resuscitation Prehospital emergency care Out-of-hospital cardiac arrest Spatial analysis Epidemiology a b s t r a c t 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 indi- vidual 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 neighbor- hood 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 ratio1.02, 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. Abbreviations: OHCA, out-of-hospital cardiac arrests; EMS, emergency medical services; CPR, cardiopulmonary resuscitation; BCPR, bystander cardiopulmonary resusci- tation; PAD, public access defibrillation; RR, relative risk; DGP, development guide plan; SCDF, Singapore Civil Defence Force; AED, automated external defibrillators; CARE, Cardiac Arrest and Resuscitation Epidemiology; PAROS, Pan-Asian Resuscitation Outcomes; CAR, conditional autoregressive; ROSC, return of spontaneous circulation; ED, emergency department; OR, odds ratio; MOR, median odds ratio; SEDI, socio-economic disadvantage index.  A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.06.006. ∗ Corresponding author at: Department of Emergency Medicine, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. E-mail addresses: marcus.ong.e.h@sgh.com.sg (M.E.H. Ong), win wah@nuhs.edu.sg (W. Wah), li yang hsu@nuhs.edu.sg (L.Y. Hsu), ng yih yng@scdf.gov.sg (Y.Y. Ng), leong benjamin@yahoo.com.sg (B.S.-H. Leong), goh.e.shaun@alexandrahealth.com.sg (E.S. Goh), han nee gan@cgh.com.sg (H.N. Gan), tham.lai.peng@kkh.com.sg (L.P. Tham), charles rabind@juronghealth.com.sg (R.A. Charles), david foo@ttsh.com.sg (D.C.G. Foo), arul.earnest@duke-nus.edu.sg (A. Earnest). http://dx.doi.org/10.1016/j.resuscitation.2014.06.006 0300-9572/© 2014 Elsevier Ireland Ltd. All rights reserved.