Racial Disparities in Asthma Severity: a Comparison Between Black and White Adult Asthmatics in the Severe Asthma Research Program

Asthma is a complex respiratory disease that has been increasing in prevalence in the United States since 1980 despite advances in treatment. Approximately 32.6 million Americans have had asthma at one point in their lives; while 22.2 million Americans are currently diagnosed with asthma. Severe asthma occurs in approximately 10% of those asthmatics. A distinct racial disparity exists within the severe asthma population, with Blacks having a greater likelihood of having poorly controlled disease compared to their White counterparts. The factors that contribute to this disparity are not truly known; however, it has been suggested that genetics, the environment, and socioeconomics play a role in the disparity.This dissertation focused on the role that biologic, genetic, and socioeconomic factors play in the development of severe asthma using data from the Severe Asthma Research Program (SARP). The overall hypothesis was that Blacks are predisposed to an allergic, early onset asthma phenotype, which fundamentally differs from the asthma observed in Whites on the basis of biologic/genetic differences in disease process. The overall aim of this study is to assess the extent to which the racial disparity in asthma is attributable to the differences in the pathobiology of asthma. The first paper sought to assess the extent to which racial disparities between Black and White adult asthmatics with severe asthma are attributable to physiologic, immunoinflammatory, and sociodemographic variables. The second paper, utilizing the results from paper 1, examined the factors that drive the increased production of immunoglobulin E (IgE) in Blacks, as well as the primary factors that contribute to severe asthma in Blacks with high IgE. The third paper presents some of the policy issues that affect the racial disparity seen in severe asthma and five recommendations that will aid in the reduction of the widening gap between Black and White asthmatics. IgE, along with family history of asthma, were shown to be a strong predictors of severe asthma in Blacks, while comorbidities were predictors for Whites. The public health significance of this study is that different interventions can now be created to effectively treat asthma in Blacks versus Whites