title: Is female sex associated with increased survival after out-of-hospital cardiac arrest?
abstract: OBJECTIVE
  To evaluate survival after out-of-hospital cardiac arrest in relation to sex.
  
  
  METHODS
  All patients with out-of-hospital cardiac arrest included in the Swedish Cardiac Arrest Registry between 1990 and 2000 in whom cardiopulmonary resuscitation (CPR) was attempted and who did not have a crew witnessed arrest were included. The registry covers 85% of the inhabitants of Sweden (approximately 8 million inhabitants). P-values were adjusted to differences in age. Survival was defined as patients being hospitalised alive and being alive one month after cardiac arrest. In all, 23,797 patients participated in the survey of which 27.9% were women.
  
  
  RESULTS
  Among women 16.4% were hospitalised alive versus 13.2% among men ( P<0.001). After one month 3.0% among women were alive versus 3.4% among men (NS). In a multivariate analysis considering differences in age and various factors at resuscitation female sex was an independent predictor for patients being hospitalised alive (odds ratio 1.66; 95% confidence limits 1.49-1.84) and for being alive after one month (odds ratio 1.27; 95% confidence limits 1.03-1.56). Women differed from men as they were older ( P<0.001 ), had a lower prevalence of witnessed cardiac arrest ( P=0.01), a lower occurrence of bystander CPR (P<0.001), a lower occurrence of ventricular fibrillation as initial arrhythmia (P<0.001) and a lower occurrence of cardiac disease judged to be the cause of cardiac arrest ( P<0.0001 ). On the other hand they had a cardiac arrest at home more frequently ( P<0.001 ).
  
  
  CONCLUSIONS
  Among patients suffering out-of-hospital cardiac arrest in Sweden which was not crew witnessed and in whom resuscitation efforts were attempted, female sex was associated with an increased survival.
authors.affiliation: Division of Cardiology, Sahlgrenska University Hospital, S-41345 Goteborg, Sweden. johan.herlitz@hjl.gu.se
authors.forename: Johan
authors.initials: J
authors.lastname: Herlitz
authors.forename: Johan
authors.initials: J
authors.lastname: Engdahl
authors.forename: Leif
authors.initials: L
authors.lastname: Svensson
authors.forename: Marie
authors.initials: M
authors.lastname: Young
authors.forename: Karl-Axel
authors.initials: KA
authors.lastname: Angquist
authors.forename: Stig
authors.initials: S
authors.lastname: Holmberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation / Q000379:methods / Q000401:mortality*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D012042:Registries; D018570:Risk Assessment; D012737:Sex Factors; D016019:Survival Analysis; D013548:Sweden