Racial differences in biologic predictors of severe asthma: Data from the Severe Asthma Research Program.
BACKGROUND
Biologic factors are known to contribute to asthma severity. It is unknown whether these factors differentially contribute to asthma severity in black compared with white subjects.


OBJECTIVE
We sought to assess the extent to which racial disparities between black and white subjects with severe asthma are attributable to physiologic, immunoinflammatory, and sociodemographic variables.


METHODS
Black and white asthmatic adults enrolled in a cross-sectional study focused on severe asthma were evaluated. Severe asthma was identified by using the American Thoracic Society definition. After initial univariable analyses, unconditional logistic regression models were used to estimate the probability of having severe asthma for black and white subjects.


RESULTS
Differences in severe asthma in black compared with white subjects were observed. In univariable analysis IgE level was not associated with severe asthma in black or white subjects, whereas in multivariable analysis IgE level was significantly associated with severe asthma for black subjects (P = .014) but not for white subjects. The odds of having severe asthma more than doubled for black subjects with 2 or more family members with asthma (P = .026), whereas the odds of severe asthma for white participants with a strong family history of asthma decreased by almost half (P = .05). Atopy was negatively associated with severe asthma in both races in univariable analysis but remained significant only in black subjects, whereas comorbidities were associated with severe asthma in white subjects.


CONCLUSIONS
Biologic factors were distinctly associated with severe asthma only in black subjects. Studies that incorporate comprehensive evaluation of biologic factors associated with asthma might lead to the development of therapies that target biologic abnormalities in black subjects.
University of Pittsburgh, USA. gamble.christy@gmail.com
Christy
C
Gamble
Evelyn
E
Talbott
Ada
A
Youk
Fernando
F
Holguin
Bruce
B
Pitt
Lori
L
Silveira
Eugene
E
Bleecker
William
W
Busse
William
W
Calhoun
Mario
M
Castro
Kian Fan
KF
Chung
Serpil
S
Erzurum
Elliot
E
Israel
Sally
S
Wenzel
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D044383:Black People; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D012720:Severity of Illness Index; D044465:White People
D007073:Immunoglobulin E