Racial disparities in asthma-related health outcomes in severe or difficult-to-treat asthma.

BACKGROUND: The underlying reasons for racial disparities in asthma morbidity are not well understood. Multivariate epidemiologic studies evaluating the presence and extent of racial differences in a large cohort of adults with severe or difficult-to-treat asthma are lacking. OBJECTIVE: To analyze an extensive array of clinical and patient-reported outcomes, using multivariate analysis with a sequential approach, to explain racial differences in asthma-related outcomes in one of the largest cohorts of difficult-to-treat asthmatic patients. METHODS: Black and white patients (> or = 18-years-old at baseline) were included (n = 2,128). Differences between the 2 racial groups were assessed using several outcome measures at month 12. Assessments were adjusted for confounding variables using a sequence of statistical models. RESULTS: Most patients were white (88.6%). Blacks were slightly younger, less educated, and more likely to live in urban areas than whites. Blacks were more likely to have severe asthma and to be treated with 3 or more long-term controllers. Poorer quality of life, more asthma control problems, and higher risk of emergency department visits were observed in blacks compared with whites; differences were not explained by adjustment for broad sets of confounding variables. Differences in asthma-related health outcomes remained statistically significant after adjusting for asthma severity. CONCLUSIONS: Asthma is a serious health problem in blacks and is not explained by differences in demographics, severity, or other health conditions.