A University of Chicago study of more than 4,000 people who suffered a cardiac arrest found that the likelihood of having bystanders perform cardiopulmonary resuscitation (CPR) is associated with two neighborhood characteristics: the frequency of cardiac arrests and the racial mix of the neighborhood.
More cardiac arrests in a neighborhood increased the odds of a victim receiving CPR, probably by raising the community's awareness of the risks of sudden cardiac death and knowledge of CPR. Rapid CPR can double or triple the odds of survival.
More surprising, those in racially integrated neighborhoods were more than twice as likely to receive CPR. In those neighborhoods, which are somewhat uncommon in Chicago, more than 40 percent of those having a cardiac arrest received help from a bystander.
People who had a cardiac arrest in a predominately white neighborhood -- defined as fewer than ten percent African American or Hispanic residents -- were less than half as likely to get CPR as those in an integrated neighborhood. The frequency was lower still in predominately black neighborhoods. Most of the arrests (84.7%) occurred at the victim's home.
Neither socioeconomic status, nor the number of older residents, nor the occupational or educational characteristics of the neighborhoods appeared to influence CPR provision.
"We believe this is the first report of a negative health effect of living in a segregated white neighborhood," said lead author Jack Iwashyna, a third-year student in the Pritzker School of Medicine at the University of Chicago who began the project as a graduate student in the University's Harris School of Public Policy.
The study, "Neighborhoods Matter: A Population-Based Study of Provision of Cardiopulmonary Resuscitation," was published in the October issue of the Annals of Emergency Medicine. It was designed to help determine why so few people receive CPR.
Although there were witnesses to the moment of arrest in nearly half (47.4%) of the 4,379 cases in this study, fewer than a quarter (22.7%) received CPR. The low rate of CPR is one of the reasons that death rates are so high, more than 95 percent, following an out-of-hospital cardiac arrest in a big city like Chicago, New York or Los Angeles.
The researchers -- emergency medicine specialist Lance Becker, M.D., medical sociologist Nicholas Christakis, M.D., Ph.D., and Iwashyna, all from the University of Chicago -- started with a data base known as the CPR Chicago project, which includes information on all (about 10 a day) out-of-hospital cardiac arrests cared for by the Chicago Emergency Medical Services system from January 1, 1987, to December 31, 1988.
They compared the frequency of bystander CPR with the demographic data from the 1990 census, which divides the city into small geographic areas, usually just a few city blocks, housing an average of about 4,000 people.
Why integration made such a difference is not clear. "Sociologists have suggested that integrated neighborhoods often house unusually strong local institutions," said Christakis, "or that they may attract more 'socially conscious' residents, but this study was not designed to measure either factor."
"The key finding, from an epidemiologic standpoint," added Iwashyna, "is that neighborhood characteristics appear to be more important than the characteristics of the cardiac-arrest victim in explaining why people receive CPR. This suggests that if we can look more closely at neighborhoods that perform best, and that often seems to mean integrated neighborhoods, we can use them as models to develop programs for other neighborhoods where people are not receiving CPR."
Journal
Annals of Emergency Medicine