Association between sex and survival after non-traumatic out of hospital cardiac arrest: A systematic review and meta-analysis

Epidemiology and outcome of out-of-hospital cardiac arrest in Salt Lake City: Sex-based investigations

Objectives

Prior research indicates sex disparities in the incidence and outcomes of out-of-hospital cardiac arrest (OHCA). This study investigates the presence of such differences in Salt Lake City, Utah.

Methods

We analyzed data from the Salt Lake City Fire Department (2008‒2023). We included adults with non-traumatic OHCA. We calculated the annual incidence of OHCA and examined sex-specific survival outcomes using multivariable logistic regression, adjusting for OHCA characteristics known to be associated with survival.

Results

The annual incidence of OHCA was 76 per 100,000 person-years. Among the 894 OHCA cases included in the analysis, 67.5% were males, 37.3% achieved return of spontaneous circulation (ROSC), and 13.6% survived hospital discharge. Unadjusted analysis revealed that males had significantly higher OHCA in public locations (43.9% vs. 28.6%), witnessed arrests (54.5% vs. 47.8%), and shockable rhythms (33.3% vs. 22.9%). Males also showed higher rates of ROSC (37.5% vs. 36.9%), hospital discharge survival (14.5% vs. 11.7%), and neurologically intact survival. After adjusting for the OHCA characteristics, there was no significant differences between males and females in ROSC, survival to hospital discharge, and favorable neurological function with adjusted odds ratios (male vs. female) of 0.92 (95% confidence interval [CI] 0.73‒1.16), 0.85 (95% CI 0.59‒1.22), and 0.92 (95% CI 0.62‒1.40), respectively.

Conclusion

Approximately, 128 adults suffer OHCA in Salt Lake City annually. Males initially showed higher crude survival rates, but after adjusting for OHCA characteristics, no significant sex differences in survival outcomes were found. Enhancing OHCA characteristics could benefit both sexes. Investigations into the relationship between sex- and region-specific factors influencing OHCA outcomes are needed.

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

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 clinical 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 categorized 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.

Underlying reasons for sex difference in survival following out-of-hospital cardiac arrest: a mediation analysis

AIMS

Previous studies have indicated a poorer survival among women following out-of-hospital cardiac arrest (OHCA), but the mechanisms explaining this difference remain largely uncertain.This study aimed to assess the survival after OHCA among women and men and explore the role of potential mediators, such as resuscitation characteristics, prior comorbidity, and socioeconomic factors.

METHODS AND RESULTS

This was a population-based cohort study including emergency medical service-treated OHCA reported to the Swedish Registry for Cardiopulmonary Resuscitation in 2010-2020, linked to nationwide Swedish healthcare registries. The relative risks (RR) of 30-day survival were compared among women and men, and a mediation analysis was performed to investigate the importance of potential mediators. Total of 43 226 OHCAs were included, of which 14 249 (33.0%) were women. Women were older and had a lower proportion of shockable initial rhythm. The crude 30-day survival among women was 6.2% compared to 10.7% for men [RR 0.58, 95% confidence interval (CI) = 0.54-0.62]. Stepwise adjustment for shockable initial rhythm attenuated the association to RR 0.85 (95% CI = 0.79-0.91). Further adjustments for age and resuscitation factors attenuated the survival difference to null (RR 0.98; 95% CI = 0.92-1.05). Mediation analysis showed that shockable initial rhythm explained ∼50% of the negative association of female sex on survival. Older age and lower disposable income were the second and third most important variables, respectively.

CONCLUSION

Women have a lower crude 30-day survival following OHCA compared to men. The poor prognosis is largely explained by a lower proportion of shockable initial rhythm, older age at presentation, and lower income.

Comparison of smokers' mortality with non-smokers following out-of-hospital cardiac arrests: a systematic review and meta-analysis

OBJECTIVE

Although some studies have linked smoking to mortality after out-of-hospital cardiac arrests (OHCAs), data regarding smoking and mortality after OHCAs have not yet been discussed in a meta-analysis. Thus, this study conducted this systematic review to clarify the association.

METHODS

The study searched Medline-PubMed, Web of Science, Embase and Cochrane libraries between January 1972 and July 2022 for studies that evaluated the association between smoking and mortality after OHCAs. Studies that reportedly showed relative risk estimates with 95% confidence intervals (CIs) were included.

RESULTS

Incorporating a collective of five studies comprising 2477 participants, the analysis revealed a lower mortality risk among smokers in the aftermath of OHCAs compared with non-smokers (odds ratio: 0.77; 95% CI 0.61-0.96; P < 0.05). Egger's test showed no publication bias in the relationship between smoking and mortality after OHCAs.

CONCLUSIONS

After experiencing OHCAs, smokers had lower mortality than non-smokers. However, due to the lack of data, this 'smoker's paradox' still needs other covariate effects and further studies to be considered valid.

Gender-related differences in adults concerning frequency, survival and treatment quality after out-of-hospital cardiac arrest (OHCA): An observational cohort study from the German resuscitation registry

BACKGROUND

In Germany approximately 20,500 women and 41,000 men were resuscitated after out-of-hospital cardiac arrest (OHCA) each year. We are currently experiencing a discussion about the possible undersupply of women in healthcare. The aim of the present study was to examine the prevalence of OHCA in Germany, as well as the outcome and quality of resuscitation care for both women and men.

METHODS

We present a cohort study from the German Resuscitation Registry (2006-2022). The quality of care was assessed for both EMS and hospital care based on risk-adjusted survival rates with the endpoints: "hospital admission with return of spontaneous circulation" (ROSCadmission) for all patients and "discharge with favourable neurological recovery" (CPC1/2discharge) for all admitted patients. Risk adjustment was performed using logistic regression analysis (LRA). If sex was significantly associated with survival, a matched-pairs-analysis (MPA) followed to explore the frequency of guideline adherence.

RESULTS

58,798 patients aged ≥ 18 years with OHCA and resuscitation were included (men = 65.2%, women = 34.8%). In the prehospital phase the male gender was associated with lower ROSCadmission-rate (LRA: OR = 0.79, CI = 0.759-0.822). A total of 27,910 patients were admitted. During hospital care, men demonstrated a better prognosis (OR = 1.10; CI = 1.015-1.191). MPA revealed a more intensive therapy for men both during EMS and hospital care. Looking at the complete chain of survival, LRA revealed no difference for men and women concerning CPC1/2discharge (n = 58,798; OR = 0.95; CI = 0.888-1.024).

CONCLUSION

In Germany, 80% more men than women experience OHCA. The prognosis for CPC1/2discharge remains low (men = 10.5%, women = 7.1%), but comparable after risk adjustment. There is evidence of undersupply of care for women during hospital treatment, which could be associated with a worse prognosis. Further investigations are required to clarify these findings.

Sex Difference on Neurological Outcomes and Post-Cardiac Arrest Care in Out-of-Hospital Cardiac Arrest Patients Treated with Targeted Temperature Management: Post-Hoc Study of a Prospective, Multicenter, Observational Cohort Study

Conflicting results regarding sex-based differences in the outcomes of out-of-hospital cardiac arrest (OHCA) patients have been reported. We aimed to evaluate the association between sex and neurological outcome as well as various in-hospital process in OHCA patients treated with targeted temperature management. We retrospectively analyzed a prospective registry data collected between October 2015 and December 2018. To evaluate the effect of sex on patient outcomes, we created various multivariable logistic regression models. When the results were adjusted using resuscitation variables and in-hospital variables, there was no significant difference (OR = 1.22, 95% CI: 0.85-1.74; OR = 1.13, 95 CI: 0.76-1.68, respectively). Regarding the in-hospital course, the daily total SOFA score was similar in both sexes, whereas cardiovascular scores were higher in women on days 2 and 3. The adjusted effect of sex was not associated with the clinician's decision to perform early cardiac interventions, except for those men that had more extracorporeal membrane oxygenation (OR = 2.51, 95% CI: 1.11-5.66). The findings seems that men had more favorable 6-month neurological outcomes. However, after adjusting for confounders, there was no difference between the sexes. The results regarding in-hospital course were similar in men and women.

Association between sex and survival after out-of-hospital cardiac arrest: A systematic review and meta-analysis

The current literature on sex differences in 30-day survival following out-of-hospital cardiac arrest (OHCA) is conflicting, with 3 recent systematic reviews reporting opposing results. To address these contradictions, this systematic literature review and meta-analysis aimed to synthesize the literature on sex differences in survival after OHCA by including only population-based studies and through separate meta-analyses of crude and adjusted effect estimates. MEDLINE and Embase databases were systematically searched from inception to March 23, 2022 to identify observational studies reporting sex-specific 30-day survival or survival until hospital discharge after OHCA. Two meta-analyses were conducted. The first included unadjusted effect estimates of the association between sex and survival (comparing males vs females), whereas the second included effect estimates adjusted for possible mediating and/or confounding variables. The PROSPERO registration number was CRD42021237887, and the search identified 6712 articles. After the screening, 164 potentially relevant articles were identified, of which 26 were included. The pooled estimate for crude effect estimates (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.22-1.66) indicated that males have a higher chance of survival after OHCA than females. However, the pooled estimate for adjusted effect estimates shows no difference in survival after OHCA between males and females (OR, 0.93; 95% CI, 0.84-1.03). Both meta-analyses involved high statistical heterogeneity between studies: crude pooled estimate I2 = 95.7%, adjusted pooled estimate I2 = 91.3%. There does not appear to be a difference in survival between males and females when effect estimates are adjusted for possible confounding and/or mediating variables in non-selected populations.