Racial disparities in out-of-hospital cardiac arrest in Denmark

Introduction

American studies have pointed out racial disparities regarding sudden cardiac death occurrence and outcomes. Black individuals have higher sudden cardiac death rates and lower survival compared with white subjects (1). Although income and social status partly explain differences in outcomes (2), sudden cardiac death is 2-fold higher in black individuals after adjustment on these characteristics (3,4).

In Denmark, immigrants account for 9.1% of the population (5) but to date, no data exists regarding Out-of-Hospital Cardiac Arrest (OHCA) incidence.

Purpose

The main objective of this study was to compare the incidence of OHCA among native and immigrant individuals between 2001 and 2014 in Denmark.

Methods

This nationwide study included all patients identified from the Danish Cardiac Arrest Registry with OHCA of presumed cardiac cause between 18 and 80 years from 2001 to 2014 (6).

The primary outcome was OHCA occurrence defined as a clinical condition of cardiac arrest resulting in resuscitation efforts either by bystanders or by EMS personnel. The immigrant status was defined as native or immigrant according to the national database from Statistics Denmark. An immigrant was defined as a person born abroad whose both parents were either foreign citizens or born abroad.

The odds ratio of OHCA between immigrants and native Danes were adjusted according to age, sex, income, and education level.

Results

A total of 33,730 OHCA were recorded between 2001 and 2014. Among them, 1,684 occurred in immigrants and 32,046 in natives. Compared to natives, immigrant victims of OHCA were younger (62.0 [51.0, 71.0] vs. 66.0 [56.0, 74.0], p<0.001), and more often had a history of diabetes (20.5% vs. 14.0; p<0.001), myocardial infarction (11.9% vs. 8.7%; p<0.001) and chronic heart failure (17.0% vs. 14.7%; p<0.01). Female proportion was not statistically different between the two groups (30.2% vs. 31.3% of immigrants and natives respectively; p=0.32).

The incidence of OHCA was 61.0/100,000 person-years in natives and 35.0/100,000 person-years in immigrants (OR=0.57; 95% CI 0.54–0.60; p<0.001). Between 2001 and 2014, the OHCA incidence decreased from 71.4 [67.9–75.0] to 70.9 [68.2–73.6]/100 000 person-years in natives (p=0.99) and from 40.2 [30.8–51.5] to 36.5 [31.1–42.6] /100,000 person-years in immigrants (p=0.91) (Figure).

After logistic regression, compared to natives, the immigrant status was associated with 0.61-fold odds of OHCA when adjusting on age and sex (OR=0.61; 95% CI 0.59–0.65; p<0.001), and 0.65-fold odds of OHCA when adjusting on age, sex, income, and education level (OR=0.66; 95% CI 0.63–0.70; p<0.001).

Conclusion

This is the first study assessing the incidence of OHCA in immigrants versus natives in a European country. Despite higher cardiovascular burden, the incidence of OHCA was lower in immigrants even when adjusted on sex, age, income, and education reflecting a selection of individuals migrating to Denmark.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Fédération Française de Cardiologie