Modifiable barriers to adherence to inhaled steroids among adults with asthma: It's not just black and white

Abstract

Background: Sociobehavioral factors influence adherence to inhaled corticosteroid (ICS) in adults with asthma and warrant exploration as explanations of apparent racial disparities in adherence. Objective: The purposes of this study were to identify barriers to adherence, potentially modifiable by healthcare providers, in a group of African Americans and non–African Americans and to test modifiable barriers as explanations of racial-ethnic differences in adherence. Methods: We conducted a cohort study of 85 adults (mean age, 47 ± 15 years; 61 [72%] female; 55 [65%] African American) with moderate or severe persistent asthma to determine modifiable sociobehavioral predictors of adherence. These were knowledge of the function of ICS, patient-perceived adequacy of communication with the provider, social support, attitude (perception of risks/benefits of ICS), depression, and self-efficacy. Adherence was calculated from electronic monitoring data as the mean of the number of doses recorded per 12 hours divided by the number prescribed, truncated at 100%. Past adherence, baseline severity of symptoms, and sociodemographics were treated as fixed confounders in ordinal logistic modeling. Results: Adherence was 60% ± 30%. In bivariate analyses, favorable attitude to ICS (P = .01) was associated with better adherence. Of immutable predictors, African American race-ethnicity (P = .001), lower educational achievement (P = .01), lower household income (P = .002), and more baseline symptoms (P = .003) were associated with poorer adherence. In multivariable analysis, controlling for immutable predictors, favorable attitude was associated with adherence. Favorable attitude was associated with greater adherence in African Americans and non–African Americans. Controlling for immutable factors, the race-adherence relationship was not mediated by the mutable factors, but economic factors (income and insurance) were mediators. Conclusion: Attitude is strongly related to adherence but does not mediate the effect of race-ethnicity. (J Allergy Clin Immunol 2003;111:1219-26.)