Disparities in process and outcome measures among adults with persistent asthma

Objective: Disparities in asthma-related care are not well understood. Such disparities are important to understand, since regular use of controller medications can prevent future exacerbations in populations with persistent asthma. The objective of this study was to examine the association of race/ethnicity with use of controller medications, the ratio of controller medications to rescue medication, emergency department (ED) utilization and asthma-related quality of life, among a population with persistent asthma.

Methods: We examined survey and administrative data for 2,021 adult persistent asthmatics enrolled in a large group model HMO located in the western United States. Persistent asthmatics were identified during calendar year 1999 using HEDIS inclusion criteria. In Fall 2000, the same patients were surveyed regarding quality of life using the Mini Asthma Quality of Life Questionnaire (AQLQ), a disease-specific quality of life questionnaire (1=lowest QOL, 7=highest QOL). Patients were also asked to self-identify their race/ethnicity on the survey. Use of controller medications, the ratio of controller medications to rescue medication and ED utilization were measured via an electronic medical record during calendar year 2001.

Multiple Logistic Regression was used to evaluate the independent effect of race/ethnicity (White vs. Hispanic/African-American/Other Race) with any controller use (use vs. non-use), medication ratio greater than 0.5 (vs. < 0.5), any asthma-related ED utilization (vs. no use); adjusting for: demographics, income, years of education, smoking status, asthma severity and satisfaction with access. Linear regression was used to evaluate the independent effect of race/ethnicity with AQLQ scores, adjusting for the same measures.

Results: After adjusting for other factors, African-Americans were more likely to report asthma-related ED utilization (OR = 3.7, 95% CI = 1.6-3.85) compared to whites. Moreover, both Hispanics (beta coeff. = -.48, p = .02) and those of Other Race (beta coeff. = -.30, p = .01) reported lower AQLQ, compared to whites. No other differences were identified.

Conclusions: Overall, we found no racial disparities among two process-level measures, use of controller medication and appropriate medication ratios. However, disparities existed among two outcome measures, specifically ED utilization and asthma-related quality of life. Of concern, African-Americans were nearly 4 times more likely to report asthma-related ED utilization, even after adjusting for other factors, such as income and education that might explain such differences. More research is needed to better understand why such disparities exist in outcome measures among adults with persistent asthma – and if appropriate – what interventions can be undertaken to reduce these disparities.