The purpose of this study was to investigate “racial differences in the incidence of cardiac arrest and of survival after cardiac arrest” and to assess “whether these differences persist after previously recognized risk factors are taken into account.” The data, collected prospectively for the 6,451 incidents of out-of-hospital “nontraumatic cardiac arrest” in Chicago, was combined from multiple sources including hospitals, reports and questionnaires completed by paramedics, and dispatchers. Among the victims, there were 114 survivors (2%), 439 patients who were admitted but died in the hospital (7 %), and 5,898 patients who were pronounced dead in emergency departments (91%).

The authors found that “in all age groups, both black men and black women had higher rates of cardiac arrest than their white counterparts.” In addition, blacks were less likely to survive following an episode of cardiac arrest (0.8 % survival rate for blacks versus 2.6% for whites). Despite higher incidence rates for the black population, the authors found that they were less likely to be admitted to a hospital (6.3% of blacks compared to 10.5% of whites). Of the subgroup admitted to a hospital, “13 percent of the black patients (24 of 183) survived to discharge, as compared with 25 percent of the white patients (84 of 336) (chi-square = 10.2, 1 df; P=0.001).” In other words, “survival for blacks was 52 percent of that for whites.” After controlling for response time and initial rhythm of ventricular fibrillation or ventricular tachycardia, “the survival rate for blacks was lower than that for whites.” If interpreted as mortality rates, the data suggest that, in Chicago, mortality from cardiac arrest for “blacks would be 99 percent.”

In “considering the influence of race as compared with that of the continuous variable of age and the interval of the arrival of the ambulance,” the investigators examined “the effect of being black in terms of an equivalent change in these variables for a comparable white person.” They found that “all other factors held constant, it would require a difference of 69 years of age or of 8.3 minutes in the time from the 911 call to the response in order to equalize the odds for blacks and whites.”

The authors conclude that the “efforts to improve survival in the black community begin with a detailed examination of the chain of survival and its links: early access, early CPR, early defibrillation, and early advanced cardiac support,” and since “cardiac arrest is often a late manifestation of longstanding cardiovascular disease, we should extend the chain of survival to include comprehensive health care services.”