Emory Study Examines Disparities Among Asthma Patients

The reason black asthma patients tend to have more severe health outcomes than white asthma patients may be due to socioeconomic and environmental inequalities rather than genetic differences, according to a study conducted by Emory researchers published in the Journal of Allergy and Clinical Immunology.

Black asthma patients tend to visit the emergency room and have higher mortality rates due to asthma, said Anne Fitzpatrick, first author of the study and director of the Asthma Clinical Research Program in the Emory School of Medicine. Fitzpatrick added that she has seen exacerbated asthma burden in black patients firsthand through clinical practices at Emory and Children’s Healthcare of Atlanta (CHOA).

“Some of these [patients] have some of the most severe forms of asthma I have ever seen, and they suffer from asthma symptoms almost every day,” Fitzpatrick said.

Senior Biostatistician at Emory’s Pediatric Research Center Scott Gillespie said past studies that compared how frequently different racial groups visit the emergency department have failed to account for disparities between racial groups, such as unemployment rates, household incomes, insurance, education and environmental exposures. Gillespie joined the project to examine these differences and their effects using an inverse probability treatment weight (IPTW) statistical model.

“It’s like comparing apples to oranges if you just look at the raw data,” Gillespie said. “We had to find a way to balance out these two groups with regard to all the factors that could affect their use of the emergency department.”

Frances Eun-Hyung Lee, director of the Asthma, Allergy and Immunology Program at Emory, said this study has added more clarity to an “area of controversy.” Some researchers previously believed genetics was the primary reason for disparities in asthma severity. However, results from this study suggest these disparities could also be a result of socioeconomic and environmental exposures, she said.

Without accounting for confounding variables, the odds of a black participant going to the emergency department for asthma in a year was 2.19 times higher than that of a white participant, according to Gillespie. However, when socioeconomic biases were removed, the odds of a black participant visiting the emergency department for asthma treatment was only 0.91 compared to that of a white participant.

In a third model, which also considered environmental factors such as exposure to tobacco smoke and water damage, whites were also more likely than blacks to visit the emergency department.

“After you consider the confounding variables, you realize that new policies and new interventions tailored specifically toward African Americans can really help drive down health disparities and, hopefully, eliminate them in the future,” Gillespie said.

The National Institutes of Health and National Heart, Lung and Blood Institute funded the study through the Severe Asthma Research Program, a group of seven U.S. institutions researching factors that lead to worse asthma symptoms in certain populations. Fitzpatrick’s study examined data from a national registry with one year of observation time.

“Because the registry was national, it was representative of the country rather than just a pocket of patients here in Atlanta,” Gillespie said.

Fitzpatrick does not currently have any plans for follow-up studies. She said, however, that she is interested in designing studies that use this information for practical purposes. Fitzpatrick added that she would like to learn how to more effectively deliver care to these underserved groups, such as through mobile healthcare systems.

“The most important take-home message is that there are plenty of intervention strategies for us to look at,” Fitzpatrick said. “We’re finding that it’s not that disease is biologically different in certain patients, but that we could just do a better job of providing them with care.”