Background: Previous studies have shown differences in adherence to inhaled corticosteroids (ICSs) by race-ethnicity, yet little is known about factors that contribute to adherence within these groups. Environmental stressors, such as crime exposure, which has been associated with asthma morbidity, might also predict ICS adherence.
Objective: We sought to identify factors associated with ICS adherence among patients with asthma and among African American patients and white patients separately.
Methods: Study patients with asthma were aged 18 to 50 years and were enrolled in a large southeast Michigan health maintenance organization between January 1, 1999, and December 31, 2001. The primary outcome, ICS adherence, was calculated by linking prescription-fill data with dosage information. Predictor variables included age, sex, race-ethnicity, measures of socioeconomic status (SES), average ICS copay, existing comorbidities, and crime rate in area of residence.
Results: Adherence information was available for 176 patients. ICS adherence was lower among African American patients (n = 75) when compared with white patients (n = 94; 40% vs 58%, respectively; P = .002). Among white patients, adherence was significantly lower for women when compared with men. Among African American patients, age and residential crime rates were positively and negatively associated with ICS adherence, respectively. Area crime remained a predictor of adherence in African American patients, even after adjusting for multiple measures of SES.
Conclusions: This study suggests that an environmental stressor, area crime, provides additional predictive insight into ICS-adherent behavior beyond typical SES factors.
Clinical implications: Better understanding of environmental factors that influence ICS adherence might aid in efforts to improve it.