Study objectives: To determine the relationship of literacy to asthma knowledge and ability to use a metered-dose inhaler (MDI) among patients with asthma.
Design: Cross-sectional survey.
Setting: Emergency department and asthma clinic at an urban public hospital.
Patients: Convenience sample of 273 patients presenting to the emergency department for an asthma exacerbation and 210 patients presenting to a specialized asthma clinic for routine care.
Interventions: Measurement of literacy with the Rapid Estimate of Adult Literacy in Medicine, asthma knowledge (20 question oral test), and demonstration of MDI technique (six-item assessment).
Measurements and results: Only 27% of patients read at the high-school level, although two thirds reported being high-school graduates; 33% read at the seventh- to eighth-grade level, 27% at the fourth- to sixth-grade level, and 13% at or below the third-grade level. Mean asthma knowledge scores (±SD) were directly related to reading levels: 15.1 ± 2.5, 13.9 ± 2.5, 13.4 ± 2.8, 11.9 ± 2.5, respectively (p < 0.01). Patient reading level was the strongest predictor of asthma knowledge score in multivariate analysis. Poor MDI technique (≤3 correct steps) was found in 89% of patients reading at less than the third-grade level compared with 48% of patients reading at the high-school level. In multivariate regression analyses, reading level was the strongest predictor of MDI technique.
Conclusions: Inadequate literacy was common and strongly correlated with poorer knowledge of asthma and improper MDI use.