Females are less likely to receive bystander cardiopulmonary resuscitation in witnessed out-of-hospital cardiac arrest: An Australian perspective

Background Bystander cardiopulmonary resuscitation (CPR) plays a significant role in survival from out-of-hospital cardiac arrest (OHCA). This study aimed to assess whether bystander CPR differed by patient sex among bystander-witnessed arrests. Methods Data on all OHCAs attended by New South Wales (NSW) paramedics between January 2017 and December 2019 was obtained from the NSW Public Health Risks and Outcomes Registry (PHROR). This observational study was restricted to bystander-witnessed cases with presumed medical aetiology. OHCA from arrests in aged care, medical facilities, and cases with an advance care directive (do-not-resuscitate) were excluded. Multivariate logistic regression was used to examine the association of patient sex with bystander CPR. Secondary outcomes were OHCA recognition, bystander AED applied, initial shockable rhythm, and survival outcomes. Results Among the 4,491 bystander-witnessed cases, females were less likely to receive bystander CPR in both private residential (Adjusted Odds ratio [AOR]: 0.82, 95%CI: 0.70-0.95) and public locations (AOR: 0.58, 95%CI:0.39-0.88). Recognition of OHCA in the emergency call was lower for females, particularly in those who arrested in public locations (84.6% vs 91.6%-males, p=0.002) and it partially explained the association of sex with bystander CPR (∼44%). There was no significant difference in OHCA recognition by sex for arrests in private residential locations (p=0.2). Females had lower rates of bystander AED use (4.8% vs 9.6%, p<0.001) however, after adjustment for arrest location and other covariates, this relationship was attenuated and no longer significant (AOR: 0.83, 95%CI: 0.60-1.12). Females were significantly less likely to record an initial shockable rhythm (AOR: 0.52, 95%CI: 0.44-0.61). Although females had greater odds of event survival (AOR: 1.34, 95%CI: 1.15 – 1.56), there was no sex difference in survival to hospital discharge (AOR: 0.96, 95%CI: 0.77-1.19). Conclusion OHCA recognition and bystander CPR provision differs by patient sex in NSW. Given their importance to patient outcomes, research is needed to understand why this difference occurs and to raise awareness of this issue to the public. What is new? What are the clinical implications? ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial n/a ### Funding Statement This work was supported by the National Health and Medical Research Council (NHMRC) of Australia partnership project grant (#1168950). In addition, and as part of the NHMRC partnership grant, the study received support from the following partner organisations: NSW Ministry of Health, Surf Life Saving NSW, Western Sydney Local Health District, NSW Ambulance, The National Heart Foundation of Australia, Michael Hughes Foundation (now merged with Heart of the Nation), Heart Support Australia, City of Parramatta, Take Heart Australia, and the NSW Data Analytics Centre. SMunot was funded by PhD scholarships from The University of Sydney centres (Westmead Applied Research Centre and Charles Perkins Centre Westmead node), JB is funded by a Heart Foundation of Australia Fellowship (##104751), JR is funded by an NHMRC Investigator Grant (GNT1143538), CS is funded by an NHMRC Practitioner Fellowship (#1154992) and NSW Health, BA is supported by an NHMRC Emerging Leadership Grant (GNT2010055). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The University of Sydney Human Research Ethics Committee Ref. no 2021/017. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data is confidential and we do not have sharing permissions.