Predictors of asthma medication nonadherence

BACKGROUND: The purpose of this study was to describe asthma medication adherence behavior and to identify predictors of inhaled corticosteroid (ICS) underuse and inhaled beta-agonist (IBA) overuse. METHODS: Self-reported medication adherence, spirometry, various measures of status, and blood for immunoglobulin E measurement were collected on 158 subjects from a larger cohort of adults with asthma and rhinitis who were prescribed an ICS, an IBA, or both. RESULTS: There was a positive association between ICS underuse and higher forced expiratory volume in one second percent (FEV 1%) predicted (P =.0 1) and a negative association with lower income (P = 0.04). IBA overuse was positively associated with greater perceived severity of asthma (P = 0.004) and negatively with higher education level (P = 0.02). CONCLUSIONS: Nonadherence to prescribed asthma therapy seems to be influenced by socioeconomic factors and by perceived and actual severity of disease. These factors are important to assess when trying to estimate the degree of medication adherence and its relationship to clinical presentation.