When studies find a link between race and something else, race is often standing in for something harder to measure than skin color, like socioeconomic status. This study looked at what underlies the fact that nonwhite people having heart attacks take longer to get lifesaving treatment than white people.

What the researchers wanted to know: What are the differences in time to therapy for people of different races, and what causes those variations?

What they did: The researchers used the National Registry of Myocardial Infarction and the American Hospital Association Survey of Hospitals to look at how long it took about 110,000 patients having a particular kind of heart attack to get therapy to clear the blocked arteries that feed the heart. These are called door-to-drug or door-to-balloon times, for the time it takes from arriving at the hospital to being given drugs or balloon angioplasty.

What they found: Black patients generally took about 20 percent longer to get heart attack treatment after getting to the hospital. White people got drugs an average of 33.8 minutes after coming through the door, compared with 41.4 minutes for black people, 36.1 minutes for Hispanics, and 37.4 for Asians. For balloon angioplasty, white people were treated in 103.4 minutes, black people in an average of 122.3 minutes, and Hispanics in 114.8 minutes. The researchers looked at variables like the kind of health insurance patients had, where they lived, and what kind of hospital they went to. They found that most of the racial and ethnic differences arose from differences in the hospitals they went to. Looking at white patients and Hispanic patients, for example, the difference in their door-to-balloon times fell by almost 75 percent when researchers accounted for the differences among the hospitals. They don't know what it was about the hospitals that made them different, though—just that it wasn't any of the variables they studied, including whether the hospital was urban or rural, teaching or non-teaching, or whether its doctors performed a lot of balloon angioplasties.

What the study means to you: Your chance of surviving a heart attack depends, in part, on how long it takes to get treatment. Even small delays matter. Researchers found a difference between hospitals but don't know what causes it. Even after accounting for hospital, there was still a difference in treatment times for white and minority patients.

Caveats: Designating race is never simple, and in this case, all the researchers had to go on was what race the hospital staff wrote down—which the patient may or may not have agreed with.

Find out more: A list of heart attack warning signs appears at www.americanheart.org

Read the article: Bradley, E.H., et al. "Racial and Ethnic Differences in Time to Acute Reperfusion Therapy for Patients Hospitalized With Myocardial Infarction." Journal of the American Medical Association. Oct. 6, 2004, Vol. 292, No. 13, pp. 1563–1572.

Abstract online: http://jama.ama-assn.org