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Clinical paper
Impact of sex of bystanders who perform
cardiopulmonary resuscitation on return of
spontaneous circulation in out-of-hospital cardiac
arrest patients: A retrospective, observational
study
Shunsuke Nakamura
a
, Tsuyoshi Nojima
a,*
, Takafumi Obara
a
, Takashi Hongo
a
,
Tetsuya Yumoto
a
, Takashi Yorifuji
b
, Atsunori Nakao
a
, Hiromichi Naito
a
Abstract
Background: The impact of the sex of bystanders who initiate cardiopulmonary resuscitation (CPR) on out-of-hospital cardiac arrest (OHCA)
patients has not been fully elucidated. This study aims to investigate the association between the sex of bystanders who perform CPR and the clin-
ical outcomes of OHCA patients in real-world clinical settings.
Methods: We conducted a retrospective, observational study using data from the Okayama City Fire Department in Japan. Patients were catego-
rized based on bystanders’ sex. Our primary outcomes were return of spontaneous circulation (ROSC). Our secondary outcome was 30-day survival
and 30-day favorable neurological outcome, defined as Cerebral Performance Category score of 1 or 2. Multivariable logistic regression analysis was
used to examine the association between these groups and outcomes.
Results: The study included 3,209 patients with a comparable distribution of male (1,540 patients: 48.0%) and female bystanders (1,669 patients:
52.0%) between the groups. Overall, 221 (6.9%) ROSC at hospital arrival, 226 (7.0%) patients had 30-day survival, and 121 (3.8%) patients had 30-
day favorable neurological outcomes. Bystander sex (female as reference) did not contribute to ROSC at hospital arrival (adjusted OR [aOR] 1.11,
95% CI: 0.76–1.61), 30-day survival (aOR 1.23, 95% CI: 0.83–1.82), or 30-day favorable neurological outcomes (aOR 0.66, 95% CI: 0.34–1.27).
Basic life support education experience was a bystander factor positively associated with ROSC. Patient factors positively associated with ROSC
were initial shockable rhythm and witness of cardiac arrest.
Conclusion: There were no differences in ROSC, 30-day survival, or 30-day neurological outcomes in OHCA patients based on bystander sex.
Keywords: Layperson, Sex difference, Heart arrest, Education
Introduction
Bystander cardiopulmonary resuscitation (CPR) plays a critical role in
improving survival of patients following out-of-hospital cardiac arrest
(OHCA).
1–4
In witnessed OHCA, patients who received bystander
CPR had approximately twice the one-month survival rate compared
to those who did not receive bystander CPR.
5
Bystanders who may
not recognize cardiac arrest or have no prior CPR experience are
encouraged to perform dispatcher-assisted CPR (DA-CPR), thereby
increasing the chance of survival.
6–9
DA-CPR assists CPR by allow-
ing the dispatcher to determine whether the patient is in cardiac arrest
status and to provide instructions for chest compressions and ventila-
tion or only chest compressions.
9,10
DA-CPR has a lower survival rate
compared to public bystander-initiated CPR
9
; this disparity in survival
may be associated with the gender of those performing DA-CPR,
10
although this relationship has not been clearly examined.
There have been studies about bystander characteristics includ-
ing gender difference and CPR performance. However, since most
https://doi.org/10.1016/j.resplu.2024.100659
Received 12 January 2024; Received in revised form 27 April 2024; Accepted 30 April 2024
2666-5204/Ó2024 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.
org/licenses/by-nc-nd/4.0/).
* Corresponding author.
E-mail address: t.nojima1002@gmail.com (T. Nojima).
RESUSCITATION PLUS18 (2024) 100659
Available online at www.sciencedirect.com
Resuscitation Plus
journal homepage: www.elsevier.com/locate/resuscitation-plus
studies were conducted using mannequin simulation
11–13
or in
unique environment where there are gender differences in BLS edu-
cation due to factors such as military service,
3
the impact of the sex
of bystanders who initiate CPR on OHCA patients has not been fully
elucidated.
In this study, we evaluated the impact of bystander sex on out-
comes in situations where there are no significant CPR educational
background differences. The primary objective of this study was to
assess the relationship between bystander sex and clinical out-
comes of patients experiencing OHCA in real-world clinical settings
in Japan.
Methods
Study design
This retrospective, observational cohort study complied with the prin-
ciples of the Declaration of Helsinki. Data on OHCA patients man-
aged from January 2012 to December 2020 were obtained from
the Okayama City Fire Department database. This study was
approved by the Okayama University ethics committee (K2209-13).
Okayama City Fire Department database
This database includes OHCA patients registered by the Okayama
City Fire Department. The following data were registered in the data-
base: patient information (Sex, age, initial rhythm, cause of cardiac
arrest, return of spontaneous circulation [ROSC], survival at dis-
charge, Cerebral Performance Category [CPC] score after 30 days),
prehospital resuscitation information (witnessed cardiac arrest, loca-
tion of cardiac arrest, bystander CPR, emergency medical service
[EMS] response time), and bystander CPR information (bystander’s
sex, bystander’s basic life support [BLS] education experience).
Arrest location was classified (home/residence, non-home/public)
according to previous literature.
14
EMS response time was defined
as time from dispatch to EMS contact. Individual bystander data
was first obtained by the dispatcher, then confirmed by EMS person-
nel on the scene. Information on bystanders who initiated CPR was
recorded. Bystander CPR was defined as layperson-initiated CPR on
the scene. The cause of cardiac arrest, 30-day survival, and 30-day
CPC scores were provided by the physicians at the receiving
hospital.
Okayama City emergency medical system
Okayama City, a mix of urban and suburban areas, covers a 789 km
2
area and has the population of approximately 700,000, with 340,000
(48.6%) males and 360,000 (51.4%) females at the time of this
study. EMS in Okayama City is operated by 20 fire stations and
one command center. EMS personnel are activated by dialing 119.
The emergency dispatcher has the role of guiding the caller through
the CPR process over the phone. The dispatchers are trained to
identify a cardiac arrest within 60 s and, if necessary, provide step-
by-step instructions to the caller for performing CPR. These instruc-
tions include guidance on chest compressions, rescue breathing,
and use of automated external defibrillators (AED) when available.
An EMS team (paramedic) with more than three ambulance crew
members is dispatched from the nearest fire station to provide imme-
diate care to OHCA patients. At least one EMS personnel capable of
emergency life-saving technique must be present on the EMS
team.
15
Specially trained emergency life-saving EMS personnel have
the authority to perform endotracheal intubation and administer adre-
naline. Almost all OHCA patients are transported to the nearest
emergency hospital. In Japan, EMS personnel are not allowed to
stop resuscitation in the field or during transport once resuscitation
has been initiated.
Patient selection, groups, endpoints
Inclusion criteria were all types of OHCA patients who were over
18 years old and received bystander CPR and were transported by
the Okayama City Fire Department from January 1, 2012, to Decem-
ber 31, 2020. Exclusion criteria were as follows: patients without
information on bystander’s sex or cardiac arrest witnessed by med-
ical staff. Eligible patients were divided into two groups based on
the sex of the bystander performing CPR, the “male bystander
CPR group” or the “female bystander CPR group.” Our primary out-
come was ROSC at hospital arrival. Secondary outcome was 30-day
survival and 30-day favorable neurological outcome. Favorable neu-
rological outcomes were defined as CPC scores of 1 or 2.
Data analysis
Continuous variables are described using medians with interquartile
ranges. Categorical variables are summarized using counts and per-
centages. The Mann-Whitney Utest or chi-square test was used as
an univariable analysis. Our primary aim is to explore the relationship
between bystander sex and clinical outcomes of OHCA patients. A
multivariable logistic regression analysis was used to adjust for fac-
tors associated with primary and secondary outcomes. The following
confounding variables were selected: age, patient’s sex (male,
female), cause of arrest (cardiac, noncardiac), witnessed cardiac
arrest (yes, no), location of cardiac arrest (home/residence, non-
home/public location), initial shockable rhythm (ventricular fibrillation,
tachycardia) at scene, EMS response time (defined as time from
patients call to EMS contact), DA-CPR, and bystander’s previous
BLS education experience (yes, no). These variables were selected
based on previous literature suggesting an association of these fac-
tors with neurological outcomes.
16,17
The results of multivariable logistic regression are described with
odds ratio (OR) and a 95% confidence interval (CI). Additionally, a
subgroup analysis was conducted based on patient sex to determine
if there was an impact of bystander sex on outcomes. A multivariable
logistic regression analysis was used to adjust for factors associated
with outcomes using the same confounding variables for adjust-
ments. A p-value < 0.05 was considered significant. Statistical anal-
ysis was performed using STATA/SE 17 (StataCorp, Lakeway, TX,
USA).
Results
Patient Characteristics
Fig. 1 is a flow diagram showing the enrollment process for our study
population. Of 5,535 patients documented in the data during the
study period, 3,209 OHCA patients were included in this analysis,
with 1,540 (48.0%) in the male bystander CPR group and 1,669
(52.0%) in the female bystander CPR group.
Baseline clinical information of both patients and bystanders are
presented in Table 1. Among the OHCA patients, 1,678 (52.2%)
were male, the median age was 82 years, median EMS response
time was 7 min, 174 (5.4%) had shockable rhythm, 1,635 (50.9%)
had estimated cardiac origin, 1,283 (39.9%) experienced a wit-
nessed cardiac arrest, 2,920 (90.9%) had DA-CPR, and 1,162
2RESUSCITATION PLUS 18 (2024) 100659
(36.2%) had a public location of cardiac arrest. Eight hundred twenty-
six (25.7%) bystanders had past BLS education experience.
Among all OHCA patients, 221 (6.9%) had ROSC at hospital arri-
val, 226 (7.0%) had 30-day survival, and 121 (3.8%) had 30-day
favorable neurological outcomes. The male bystander CPR group
performed resuscitation for younger OHCA patients than the female
bystander CPR group (79 vs. 84 years, p< .01), while patient sex did
not differ between the two groups (809 [52.5%] vs. 869 [52.1%],
p= 0.79). The female bystander group had a higher proportion of
BLS education experience compared with the male bystander group
(267 [17.3%] vs. 559 [33.5%], p< .01).
Impact of bystander sex on outcomes
The impact of bystander sex on ROSC, 30-day survival, and 30-day
favorable neurological outcome with univariable and multivariable
logistic regression analysis are shown in Table 2. Bystander sex (fe-
male as reference) did not contribute to ROSC (crude OR 1.19, 95%
CI: 0.91–1.56; adjusted OR [aOR] 1.11, 95% CI: 0.76–1.61), 30-day
survival (crude OR 1.43, 95% CI: 1.09–1.37; aOR 1.23, 95% CI:
0.83–1.81), 30-day favorable neurological outcomes (crude OR
1.36, 95% CI: 0.94–1.96; aOR 0.66, 95% CI: 0.34–1.27). The results
showed that the presence of initial shockable rhythm (aOR 4.92,
95% CI: 2.89–8.38), witnessed cardiac arrest (aOR 2.45, 95% CI:
1.67–3.61), and bystander BLS education experience (aOR 1.42,
95% CI: 1.13–1.86) were associated with ROSC.
Subgroup analysis
Subgroup analyses were performed according to patient sex
(Table 3). Male patients had a higher proportion of ROSC when
the bystander was male compared to female (male 71/809 [8.8%]
vs. female 55/869 [6.3%]). On the other hand, when patients were
female, the proportion of ROCS with a female bystander was higher
(male 44/731 [6.0%] vs. female 51/800 [6.4%]). However, bystander
sex had no significant effect on ROSC, regardless of patient sex after
adjustment (male patients: aOR 1.29, 95% CI: 0.78–2.11, female
patients: aOR 0.88, 95% CI: 0.45–1.62).
Discussion
In this study, we found that bystander sex was not associated with
ROSC, 30-day survival, and 30-day neurological outcomes in OHCA
patients, as indicated by both the univariate and multivariate logistic
models. BLS education experience was a bystander factor associ-
ated with ROSC in these patients. Patient factors positively associ-
ated with ROSC was initial shockable rhythm, witness of cardiac
arrest.
Previous studies have established various performance metrics
for CPR quality such as chest compression depth, rate, and
recoil.
18–20
Recent studies have shown a correlation between CPR
performance and bystander sex. One study reported a difference
Fig. 1 – Flow chart showing the enrollment process for our study population. CPR; cardiopulmonary resuscitation,
OHCA; out-of-hospital cardiac arrest.
RESUSCITATION PLUS 18 (2024) 100659 3
in CPR performance in mannequin simulation based on bystander
sex,
13
indicating that females exhibited significantly lower compres-
sion depth and adequate compression rates compared to males.
Another study found that male bystanders performed deeper chest
compressions than females.
12
Additionally, another report on gender
differences in CPR effort indicated that females showed higher exer-
tion during CPR; however, these differences were due to BMI and
varying physical fitness conditions.
21
These studies suggested that
females tend to deliver lower-quality CPR compared to males. Nev-
ertheless, it is important to note that these studies were not con-
ducted in real-life situations.
In contrast, analysis of real clinical data from several studies sug-
gests that there is no significant difference in CPR performance
based on bystander sex. Takei et al. conducted a study related to
bystander CPR, focusing on emergency medical technician (EMT)
assessments of chest compression quality. They found no difference
in CPR quality based on bystander sex.
22
Their study also high-
lighted that effective CPR was linked to the presence of multiple res-
cuers, bystander initiative, and non-elderly bystanders. Similarly,
Park et al. evaluated chest compression quality through subjective
observations by EMTs to investigate factors linked to high-quality
bystander CPR.
23
This study also revealed no variation in CPR qual-
ity based on bystander sex and highlighted bystander age as the pri-
mary factor influencing CPR quality. One study from Korea
highlighted the effectiveness of CPR performed by bystanders of dif-
ferent sexes on OHCA patient outcomes in the clinical setting; how-
ever, this study was biased due to the differences in previous CPR
education between males and females, with the majority of males
receiving CPR training in the military.
24
In this study, bystanders’
BLS education experience was also associated with favorable out-
comes. Another study in Korea investigated the relationship between
bystander sex and CPR rates, as well as interactions with patient
sex.
22
As far as we know, our present study is the first to explore
the relationship between bystander sex and prognosis in Japan,
where there are no apparent distinctions in BLS education experi-
ence between males and females in society.
Although data is conflicting, the prognosis for OHCA in females is
indicated to be worse compared to males.
25,26
Previous studies have
reported that female OHCA patients in public settings were less likely
to receive bystander CPR and AED compared with male OHCA
patients.
27
Indeed, resuscitation attempts for OHCA patients might
vary depending on the sex of the bystander or public vs. clinical set-
ting.
28,29
Bystanders may hesitate to perform resuscitation, espe-
cially for female OHCA patients, considering undressing for
resuscitation.
27
Our study did not have large sample size compared
to previous study, however, a subgroup analysis by patient revealed
no correlation in bystanders between bystanders’ sex and ROSC.
This study had several limitations. First, identifying the primary
bystander is challenging when there are multiple bystanders at the
scene. In this study, we designated the bystander who performed
CPR as the primary bystander when the EMS arrived at the scene.
Second, this study is constrained by its focus on prehospital treat-
ment, while neuro critical care management in post-cardiac arrest
syndrome was not explored. Differences in intensive care may have
Table 1 – Characteristics of OHCA patients and bystanders.
All
(n= 3,209)
Male Bystander group
(n= 1,540)
Female Bystander group
(n= 1,669)
p-value
Patient Characteristics
Sex (male), n (%) 1,678 (52.2) 809 (52.5) 869 (52.1) 0.79
Age, median [IQR] 82 [70–88] 79 [67–87] 84 [73–89] <.01
EMS response time (min),
median [IQR]
7 [5–9] 7 [5–9] 7 [5–9] 0.036
Call to hospital arrival (min),
median [IQR]
26 [20–32] 26 [20–32] 25 [20–32] <.01
Initial shockable rhythm, n (%) 174 (5.4) 96 (6.2) 78 (4.7) 0.052
Estimated cardiac origin, n (%) 1,635 (50.9) 772 (50.1) 863 (51.7) 0.37
Witnessed CA, n (%) 1,283 (39.9) 587 (38.1) 696 (41.7) 0.038
Dispatcher assisted CPR, n (%) 2,920 (90.9) 1,392 (90.4) 1,528 (91.6) 0.25
Location of CA <.01
Home/Residence, n (%) 2,047 (63.8) 1,070 (69.5) 977 (58.5)
Non-home/Public, n (%) 1,162 (36.2) 470 (30.5) 692 (41.5)
Patient outcomes
ROSC at hospital arrival, n (%) 221 (6.9) 115 (7.5) 106 (6.4) 0.21
30-day Survival, n (%) 226 (7.0) 127 (8.2) 99 (5.9) 0.01
CPC at 30 days
CPC 1, n (%) 108 (3.4) 62 (4.0) 46 (2.8)
CPC 2, n (%) 13 (0.4) 5 (0.3) 8 (0.5)
CPC 3, n (%) 24 (0.7) 17 (1.1) 7 (0.4)
CPC 4, n (%) 81 (2.5) 43 (2.8) 38 (2.3)
CPC 5, n (%) 2,983 (92.9) 1,413 (91.8) 1,570 (94.1)
30-day favorable neurological outcome, n (%) 121 (3.8) 67 (4.4) 54 (3.2) 0.098
Bystander Characteristics
BLS education experience, n (%) 826 (25.7) 267 (17.3) 559 (33.5) <.01
Favorable neurological outcome was defined as CPC 1 or 2.
OHCA: out-of-hospital cardiac arrest, IQR: interquartile range, EMS: emergency medical services, BLS: basic life support, CA: cardiac arrest, CPR: car-
diopulmonary resuscitation, ROSC: return of spontaneous circulation, CPC: Cerebral Performance Category.
4RESUSCITATION PLUS 18 (2024) 100659
had an impact on neurological outcomes. Third, important factors for
investigation regarding quality of CPR such as chest compression
rate, depth, fraction, interruption time, first responder intervention
time, and/or early defibrillation were not documented in this study.
Fourth, due to retrospective design of the study, we must acknowl-
edge that uncaptured data on other characteristics of bystander per-
sonnel such as age, duration of CPR, use of AED, and time interval
between onset and BLS training, may impact outcomes. Fifth, our
patients were all from a single geographic region with a relatively
small sample size. In addition, it should be noted that racial differ-
ence could not be considered in this study. Sixth, the etiology of car-
diac arrest is described by a binary variable (cardiac/non-cardiac);
however, instructions to bystanders (DA-CPR) and clinical outcomes
may vary according to different etiologies. Finally, pre-arrest CPC
scores of OHCA patients could not be obtained; therefore, it cannot
be ruled out that any low CPC scores were present pre-arrest.
Table 2 – Multivariable logistic regression analysis examining the impact of bystander sex on ROSC, 30-day
survival, and 30-day favorable neurological outcomes.
n / N (%) Crude OR
(95% CI)
Adjusted OR (95% CI)
ROSC at hospital arrival
Patient factor
Sex (male) 126/1,678 (8) 1.23 (0.93–1.62) 0.99 (0.67–1.45)
Age 0.98 (0.97–0.99) 0.99 (0.98–1.00)
EMS response time 1.00 (0.97–1.04) 1.00 (0.95–1.06)
Initial shockable rhythm 37/174 (21) 7.93 (5.23 – 12.0) 4.92 (2.89–8.38)
Estimated cardiac origin 121/1,635 (7) 1.18 (0.90 – 1.55) 1.02 (0.68–1.53)
Witnessed CA 155/1,283 (12) 3.87 (2.88 – 5.21) 2.45 (1.67–3.61)
Dispatcher assisted CPR 191/2,920 (7) 0.60 (0.40 – 0.91) 1.39 (0.68–2.86)
Non-home/Public location of CA 110/1,162 (9) 1.82 (1.39–2.40) 1.45 (0.96–2.18)
Bystander factor
Sex (male) 115/1,540 (7.5) 1.19 (0.91–1.56) 1.11(0.76–1.61)
BLS education experience 83/826 (10) 1.88 (1.41–2.50) 1.42 (1.13–1.86)
30-day survival
Patient factor
Sex (male) 129/1,678 (8) 1.23 (0.94–1.62) 0.61 (0.40–0.92)
Age 0.97 (0.96–0.98) 0.98 (0.97–0.99)
EMS response time 0.94 (0.89–0.98) 0.89 (0.83–0.96)
Initial shockable rhythm 61/174 (35) 17.8 (12.2–25.9) 9.24 (5.63–15.2)
Estimated cardiac origin 142/1,635 (9) 1.69 (1.28–2.23) 1.53 (0.99–2.36)
Witnessed CA 172/1,283 (13) 5.37 (3.92–7.35) 3.13 (2.08–4.71)
Dispatcher assisted CPR 189/2,920 (6) 0.47 (0.32–0.69) 0.84 (0.45–1.59)
Non-home/Public location of CA 102/1,162 (9) 1.49 (1.14–1.96) 1.18 (0.77–1.81)
Bystander factor
Sex (male) 127/1,540 (8) 1.43 (1.09–1.37) 1.23 (0.83–1.82)
BLS education experience 72/826 (9) 1.49 (1.11 – 2.01) 0.97 (0.59–1.60)
30-day favorable neurological outcomes
Patient factor
Sex (male) 79/1,628 (5) 1.75 (1.20–2.56) 0.76 (0.38–1.53)
Age 0.96 (0.95–0.97) 0.97 (0.95–0.99)
EMS response time 0.96 (0.91–1.02) 0.92 (0.82–1.03)
Initial shockable rhythm 42/174 (24) 47.9 (27.2–84.8) 17.9 (8.30–38.8)
Estimated cardiac origin 92/1,635 (6) 3.18 (2.08–4.85) 6.89 (2.30–20.7)
Witnessed CA 101/1,283 (8) 8.14 (5.01–13.2) 3.67 (1.76–7.64)
Dispatcher assisted CPR 98/2,920 (3) 0.40 (0.25–0.64) 0.74 (0.27–2.05)
Non-home/Public location of CA 65/1,162 (6) 2.11 (1.46–3.03) 2.66 (1.33–5.29)
Bystander factor
Sex (male) 67/1,540 (4) 1.36 (0.94–1.96) 0.66 (0.34–1.27)
BLS education experience 46/826 (6) 2.01 (1.37–2.95) 1.25 (0.57–2.77)
Multivariable logistic regression analysis was adjusted for patient age, patient sex, EMS response time, witnessed cardiac arrest, initial shockable rhythm, cardiac
origin, dispatcher assisted CPR, non-home/public location of cardiac arrest, bystander sex, and bystander BLS education experience.
ROSC: return of spontaneous circulation, CI: confidence interval, OR: odds ratio, EMS: emergency medical services, CA: cardiac arrest, CPR: cardiopulmonary
resuscitation, BLS: basic life support.
RESUSCITATION PLUS 18 (2024) 100659 5
Conclusion
There was no difference in ROSC, 30-day survival, and 30-day neu-
rological outcomes in OHCA patients based on sex of the bystander
who initiated CPR.
Ethics approval and consent to participate
This study conforms to the principles outlined in the Declaration of
Helsinki and was approved by the ethics committee of the Okayama
University Hospital, ID: K2209-13. Patient consent was waived for all
participants enrolled in this study because of its retrospective study
design.
Consent for publication
Not applicable.
Availability of data and materials
The datasets from this study are available from the corresponding
author upon request.
Credit authorship contribution statement
Shunsuke Nakamura: Writing – original draft, Visualization,
Methodology, Formal analysis, Conceptualization. Tsuyoshi
Nojima: Writing – review & editing, Visualization, Project administra-
tion, Methodology, Investigation, Formal analysis, Conceptualization.
Takafumi Obara: Writing – review & editing, Visualization, Formal
analysis, Conceptualization. Takashi Hongo: Writing – review &
editing, Visualization, Formal analysis. Tetsuya Yumoto: Writing –
review & editing, Visualization. Takashi Yorifuji: Writing – review
& editing, Visualization, Formal analysis. Atsunori Nakao: Writing
– review & editing, Supervision, Investigation. Hiromichi Naito:
Writing – review & editing, Visualization, Supervision, Methodology,
Investigation, Formal analysis, Conceptualization.
Declaration of competing interest
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influ-
ence the work reported in this paper.
Acknowledgements
We thank the members Okayama City Fire Department. We thank
Christine Burr for editing the manuscript.
Author details
a
Department of Emergency, Critical Care, and Disaster Medicine,
Faculty of Medicine, Dentistry, and Pharmaceutical Sciences,
Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-
8558, Japan
b
Department of Epidemiology, Faculty of Medicine,
Dentistry, and Pharmaceutical Sciences, Okayama University, 2-5-1
Shikata-cho, Kita-ku, Okayama 700-8558, Japan
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Table 3 – Subgroup analysis according to patient sex. Multivariable logistic regression analysis was used to
examine ROSC.
n/N (%) Adjusted OR (95% CI)
Male patients
Bystander sex
Male 71/809 (8.8) 1.29 (0.78–2.11)
Female 55/869 (6.3) Ref
Female patients
Bystander sex
Male 44/731 (6.0) 0.88 (0.45–1.62)
Female 51/800 (6.4) Ref
Subgroup analysis was conducted according to patients’ sex. This analysis was focused “bystander sex”. Multivariable logistic regression analysis adjusted for
patient age, EMS response time, witnessed cardiac arrest, initial shockable rhythm, cardiac origin, dispatcher assisted CPR, non-home/public location of cardiac
arrest and bystander BLS education experience.
ROSC: return of spontaneous circulation, CI: confidence interval, OR: odds ratio, EMS: emergency medical services, CPR: cardiopulmonary resuscitation, BLS:
basic life support.
6RESUSCITATION PLUS 18 (2024) 100659
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