Hospital racial composition: a neglected factor in cardiac arrest survival disparities

Abstract

Background: Racial disparities in survival after out-of-hospital cardiac arrest have been reported, but their causes remain uncertain. We sought to determine if hospital racial composition accounted for survival differences for patients hospitalized after cardiac arrest.

Methods: We evaluated hospitalizations of white and black Medicare beneficiaries (2000-2007) admitted from the emergency department to the intensive care unit with a diagnosis of cardiac arrest or ventricular fibrillation. We examined unadjusted survival rates and developed a multivariable logistic regression model that included patient and hospital factors.

Results: We analyzed 68,115 cardiac arrest admissions. Unadjusted survival to hospital discharge was worse for blacks (n = 7,942) compared with whites (n = 60,173) (30% vs 33%, P < .001). In multivariate analyses accounting for patient and hospital factors, adjusted probability of survival was worse for black patients at hospitals with higher proportions of black patients (31%, 95% CI 29%-32%) compared with predominately white hospitals (46%, 95% CI 36%-57%; P = .003). Similarly, whites had worse risk-adjusted survival at hospitals with higher proportions of black patients (28%, 95% CI 27%-30%) compared with predominately white hospitals (32%, 95% CI 31%-33%, P = .006). Blacks were more likely to be admitted to hospitals with low survival rates (23% vs 15%, P < .001).

Conclusion: Hospitals with large black patient populations had worse cardiac arrest outcomes than predominantly white hospitals, and blacks were more likely to be admitted to these high-mortality hospitals. Understanding these differences in survival outcomes may uncover the causes for these disparities and lead to improved survival for all cardiac arrest victims.

Figure 1. Adjusted survival from cardiac arrest by race and hospital racial composition

Controlling for patient (age, sex, comorbidites, inpatient concurrent diagnoses) and hospital factors (volume, ownership, teaching status, location, income, urban status, and cardiovascular procedure capability), survival by race is represented in each % black quintile. P values reflect within hospital comparisons by race. Across hospital (quintile 1 versus 5) adjusted survival was significant for blacks (p=.003) and whites (p=.006).

Figure 2. Adjusted survival for blacks and whites at hospitals with high and low survival rates from cardiac arrest

Controlling for patient and hospital factors the adjusted probability of survival by race is represented in each quintile of hospital survival rate. P values reflect within hospital comparisons by race.