Sex Differences in Incidence and Outcome of Out-of-Hospital Cardiac Arrest Within a Local Health Network

Melanie R Wittwer; Emily Aldridge; Cindy Hein; Mel Thorrowgood; Chris Zeitz; John F Beltrame; Margaret A Arstall

doi:10.3389/fcvm.2022.870696

Sex Differences in Incidence and Outcome of Out-of-Hospital Cardiac Arrest Within a Local Health Network

Front Cardiovasc Med. 2022 Apr 8:9:870696. doi: 10.3389/fcvm.2022.870696. eCollection 2022.

Authors

Melanie R Wittwer^{1

2}, Emily Aldridge^{1

2}, Cindy Hein³, Mel Thorrowgood⁴, Chris Zeitz^{1

5}, John F Beltrame^{1

5}, Margaret A Arstall^{1

2}

Affiliations

¹ Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.
² Northern Adelaide Local Health Network, Adelaide, SA, Australia.
³ College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.
⁴ SA Ambulance Service, Eastwood, SA, Australia.
⁵ Central Adelaide Local Health Network, Adelaide, SA, Australia.

Abstract

Introduction: Sex and gender differences in presentation and characteristics of out-of-hospital cardiac arrest (OHCA) are established in cohorts with presumed cardiac aetiology but not non-cardiac etiology. This study investigated the effect of sex on incidence and outcome of OHCA according to presumed and adjudicated aetiology within a local health network.

Methods: Population-based observational cohort study of emergency medical services (EMS) attended OHCAs within an Australian local health network. Cases identified from an EMS registry between 2012-2016 were linked to a hospital registry. Age-standardised incidence and baseline characteristics were stratified by sex for EMS-treated OHCA, non-EMS witnessed presumed cardiac and obvious non-cardiac sub-cohorts, and hospitalised cases. Logistic regression was used to explore the primary outcome of survival to hospital discharge.

Results: We identified 2,024 EMS-attended and 780 EMS-treated OHCAs. The non-EMS witnessed sub-cohorts comprised 504 presumed cardiac and 168 obvious non-cardiac OHCAs. Adjudicated aetiology was recorded in 123 hospitalised cases. Age-standardised incidence for women was almost half that of men across all groups. Across cohorts, women were generally older and arrested with a non-shockable initial rhythm in an area of low socioeconomic status. There was no sex difference in the primary outcome for the main EMS-treated cohort or in the non-cardiac sub-cohorts. The sex difference in outcome in the presumed cardiac sub-cohort was not present after multivariable adjustment.

Conclusions: There are sex differences in incidence and outcome of EMS-treated OHCA that appear to be driven by differences in susceptibility to cardiac arrhythmias and underlying etiology, rather than treatment delays or disparities.

Keywords: aetiology (etiology); epidemiology; gender; out-of-hospital cardiac arrest; outcomes - health care; sex; socioeconomic status.