title: Associations between gender and cardiac arrest outcomes in Pan-Asian out-of-hospital cardiac arrest patients.
abstract: BACKGROUND
  The incidence of out-of-hospital cardiac arrest (OHCA) in women is thought to be lower than that of men, with better outcomes in some Western studies.
  
  
  OBJECTIVE
  This study aimed to investigate the effect of gender on OHCA outcomes in the Pan-Asian population.
  
  
  METHODS
  This was a retrospective, secondary analysis of the Pan Asian Resuscitation Outcomes Study (PAROS) data between 2009 and 2012. We included OHCA cases which were presumed cardiac etiology, aged 18 years and above and resuscitation attempted by emergency medical services (EMS) systems. We used multi-level mixed-effects logistic regression models to account for the clustering effect of individuals within the country. Primary outcome was survival to hospital discharge.
  
  
  RESULTS
  We included a total of 40,159 OHCA cases, 40% of which were women. We found that women were more likely to be older and have an initial non-shockable arrest rhythm; they were more likely to receive bystander cardio-pulmonary resuscitation (CPR). The univariate analysis showed that women were significantly less likely to have return of spontaneous circulation (ROSC) at scene or in the emergency department (ED), and had lower rates of survival-to-admission and discharge, and poorer overall and cerebral performance outcomes. There was however, no significant gender difference on outcomes after adjustment of other confounders. Women in the reproductive age group (age 18-44 years) were significantly more likely to have ROSC at scene or in the ED, higher rates of survival-to-admission and discharge, and have better overall and cerebral performance outcomes after adjustment for differences in baseline and pre-hospital factors. Menopausal women (age 55 years and above) were less likely to survive to admission after adjusting for other pre-hospital characteristics but not after age adjustment.
  
  
  CONCLUSIONS
  Differences in survival outcomes between reproductive and menopausal women highlight a need for further investigations into the plausible social, pathologic or hormonal basis.
authors.affiliation: Medical Department, Singapore Civil Defence Force, Singapore; Department of Emergency Medicine, Singapore General Hospital, Singapore.
authors.forename: Yih Yng
authors.initials: YY
authors.lastname: Ng
authors.affiliation: Centre for Infectious Disease Epidemiology and Research, Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
authors.forename: Win
authors.initials: W
authors.lastname: Wah
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital, Singapore; Centre for Quantitative Medicine, Duke-NUS Medical School, Singapore. Electronic address: liu.nan@sgh.com.sg.
authors.forename: Nan
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Emergency Medicine, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang, China.
authors.forename: Sheng Ang
authors.initials: SA
authors.lastname: Zhou
authors.affiliation: SingHealth Emergency Medicine Residency Program, Singapore.
authors.forename: Andrew Fu Wah
authors.initials: AF
authors.lastname: Ho
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital, Singapore.
authors.forename: Pin Pin
authors.initials: PP
authors.lastname: Pek
authors.affiliation: Department of Emergency Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sang Do
authors.initials: SD
authors.lastname: Shin
authors.affiliation: Department of EMS System, Graduate School, Kokushikan University, Tokyo, Japan.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Emergency Medicine, Rajavithi Hospital, Bangkok, Thailand.
authors.forename: Nalinas
authors.initials: N
authors.lastname: Khunkhlai
authors.affiliation: Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chih-Hao
authors.initials: CH
authors.lastname: Lin
authors.affiliation: Emergency Department, Hospital Pulau Pinang, Penang, Malaysia.
authors.forename: Kwanhathai Darin
authors.initials: KD
authors.lastname: Wong
authors.affiliation: Department of Emergency Medicine, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang, China.
authors.forename: Wen Wei
authors.initials: WW
authors.lastname: Cai
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital, Singapore; Health Services and Systems Research, Duke-NUS Medical School, Singapore.
authors.forename: Marcus Eng Hock
authors.initials: ME
authors.lastname: Ong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001208:Asia / Q000453:epidemiology; D016887:Cardiopulmonary Resuscitation; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality*; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D017678:Sex Distribution; D012737:Sex Factors; D015996:Survival Rate / Q000639:trends
keywords: Gender; Out-of-hospital cardiac arrest; Registry