Income is associated with the probability to receive early coronary angiography after out-of-hospital cardiac arrest

Mediators of the Association Between Socioeconomic Status and Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review

Low socioeconomic status (SES) is associated with poor outcomes after out-of-hospital cardiac arrest (OHCA). Patient characteristics, care processes, and other contextual factors may mediate the association between SES and survival after OHCA. Interventions that target these mediating factors may reduce disparities in OHCA outcomes across the socioeconomic spectrum. This systematic review identified and quantified mediators of the SES-survival after OHCA association. Electronic databases (MEDLINE, Embase, PubMed, Web of Science) and grey literature sources were searched from inception to July or August 2023. Observational studies of OHCA patients that conducted mediation analyses to evaluate potential mediators of the association between SES (defined by income, education, occupation, or a composite index) and survival outcomes were included. A total of 10 studies were included in this review. Income (n = 9), education (n = 4), occupation (n = 1), and composite indices (n = 1) were used to define SES. The proportion of OHCA cases that had bystander involvement, presented with an initial shockable rhythm, and survived to hospital discharge or 30 days increased with higher SES. Common mediators of the SES-survival association that were evaluated included initial rhythm (n = 6), emergency medical services response time (n = 5), and bystander cardiopulmonary resuscitation (n = 4). Initial rhythm was the most important mediator of this association, with a median percent excess risk explained of 37.4% (range 28.6%-40.0%; n = 5; 1 study reported no mediation) and mediation proportion of 41.8% (n = 1). To mitigate socioeconomic disparities in outcomes after OHCA, interventions should target potentially modifiable mediators, such as initial rhythm, which may involve improving bystander awareness of OHCA and the need for prompt resuscitation.

Evaluation of Socioeconomic Position and Survival After Out-of-Hospital Cardiac Arrest in Korea Using Structural Equation Modeling

Importance

The association between low socioeconomic position (SEP) and poor survival after out-of-hospital cardiac arrest (OHCA) has not been thoroughly investigated.

Objectives

To evaluate the association between individual SEP and survival after OHCA and to identify any mediating pathways using structural equation modeling (SEM).

Design, Setting, and Participants

This is a retrospective cohort study that used data collected from January 2013 to December 2019. Participants were adults with OHCA with a presumed cardiac etiology. The study was conducted in Korea, which has a universal health insurance system. Data were analyzed from January 2022 to February 2023.

Exposures

Individual SEP was measured by insurance type (National Health Insurance [NHI] and medical aid [MA]) and premiums. SEP was categorized into 5 groups, in which NHI beneficiaries were divided into quartiles (Q1, highest quartile; Q4, lowest quartile), and MA was the lowest SEP group.

Main Outcomes and Measures

The primary outcome was survival to discharge. The association between SEP and OHCA survival was examined using multivariable logistic regression, and mediating factors were identified using SEM.

Results

A total of 121 516 patients (median [IQR] age, 73 [60-81] years; 43 912 [36.1%] female patients) were included. Compared with the NHI Q1 group, individuals with lower SEP had lower odds of survival to discharge. The adjusted odds ratios of survival to discharge were 0.97 (95% CI, 0.94-1.00), 0.88 (95% CI, 0.85-0.91), 0.91 (95% CI, 0.88-0.94), and 0.53 (95% CI, 0.50-0.56) for the NHI Q2, NHI Q3, NHI Q4, and MA groups, respectively. Several factors were found to mediate the association of SEP and survival in the total study population, with mediating proportions of 15.1% (95% CI, 11.8%-18.4%) for witnessed status, 4.8% (95% CI, 3.5%-6.0%) for bystander cardiopulmonary resuscitation provision, 41.8% (95% CI, 35.4%-48.1%) for initial rhythm, and 9.4% (95% CI, 7.4%-11.4%) for emergency department level. Among patients who survived to hospital admission, the mediation proportions were 11.8% (95% CI, 6.7%-16.9%) for witnessed status, 3.7% (95% CI, 1.3%-6.1%) for bystander cardiopulmonary resuscitation provision, 56.2% (95% CI, 41.0%-71.4%) for initial rhythm, 10.7% (95% CI, 6.1%-15.3%) for emergency department level, 20.2% (95% CI, 14.0%-26.5%) for coronary angiography, and 4.2% (95% CI, 2.2%-6.1%) for targeted temperature management.

Conclusions and Relevance

In this cohort study of patients with OHCA, lower individual SEP was significantly associated with lower survival to discharge. Potentially modifiable mediators can be targeted for public health interventions to reduce disparities in survival among patients with OHCA of different SEP.

Predicting recurrent cardiac arrest in individuals surviving Out-of-Hospital cardiac arrest

BACKGROUND

Despite improvements in short-term survival for Out-of-Hospital Cardiac Arrest (OHCA) in the past two decades, long-term survival is still not well studied. Furthermore, the contribution of different variables on long-term survival have not been fully investigated.

AIM

Examine the 1-year prognosis of patients discharged from hospital after an OHCA. Furthermore, identify factors predicting re-arrest and/or death during 1-year follow-up.

METHODS

All patients 18 years or older surviving an OHCA and discharged from the hospital were identified from the Swedish Register for Cardiopulmonary Resuscitation (SRCR). Data on diagnoses, medications and socioeconomic factors was gathered from other Swedish registers. A machine learning model was constructed with 886 variables and evaluated for its predictive capabilities. Variable importance was gathered from the model and new models with the most important variables were created.

RESULTS

Out of the 5098 patients included, 902 (∼18%) suffered a recurrent cardiac arrest or death within a year. For the outcome death or re-arrest within 1 year from discharge the model achieved an ROC (receiver operating characteristics) AUC (area under the curve) of 0.73. A model with the 15 most important variables achieved an AUC of 0.69.

CONCLUSIONS

Survivors of an OHCA have a high risk of suffering a re-arrest or death within 1 year from hospital discharge. A machine learning model with 15 different variables, among which age, socioeconomic factors and neurofunctional status at hospital discharge, achieved almost the same predictive capabilities with reasonable precision as the full model with 886 variables.

Individual socioeconomic status and risk of out-of-hospital cardiac arrest: A nationwide case-control analysis

OBJECTIVES

Area-level socioeconomic status (SES) is associated with the incidence of out-of-hospital cardiac arrest (OHCA); however, the effects of individual-level SES on OHCA occurrence are unknown. This study investigated whether individual-level SES is associated with the occurrence of OHCA.

METHODS

This case-control study used data from the nationwide OHCA registry and the National Health Information Database (NHID) in Korea. All adult patients with OHCA of a medical etiology from 2013 to 2018 were included. Four controls were matched to each OHCA patient based on age and sex. The exposure was individual-level SES measured by insurance type and premium, which is based on income in Korea. National Health Insurance (NHI) beneficiaries were divided into four groups (Q1-Q4), and medical aid beneficiaries were separately classified as the lowest SES group. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the outcomes were calculated. Stratified analyses were conducted according to age and sex.

RESULTS

A total of 105,443 cases were matched with 421,772 controls. OHCA occurred more frequently in the lower SES groups. Compared with the highest SES group (Q1), the aORs for OHCA occurrence increased as the SES decreased (aORs [95% CI] were 1.21 [1.19-1.24] for Q2, 1.33 [1.31-1.36] for Q3, 1.32 [1.30-1.35] for Q4, and 2.08 [2.02-2.13] for medical aid). Disparity by individual-level SES appeared to be greater in males than in females and greater in the young and middle-aged adults than in older adults.

CONCLUSIONS

Low individual-level SES was associated with a higher probability of OHCA occurrence. Efforts are needed to reduce SES disparities in the occurrence of OHCA.

Socioeconomic Factors and their Impact on Access and Use of Coronary and Structural Interventions

In the past few decades, the accelerated improvement in technology has allowed the development of new and effective coronary and structural heart disease interventions. There has been inequitable patient access to these advanced therapies and significant disparities have affected patients from low socioeconomic positions. In the US, these disparities mostly affect women, black and hispanic communities who are overrepresented in low socioeconomic. Other adverse social determinants of health influenced by structural racism have also contributed to these disparities. In this article, we review the literature on disparities in access and use of coronary and structural interventions; delineate the possible reasons underlying these disparities; and highlight potential solutions at the government, healthcare system, community and individual levels.