Current research shows that patients with less health literacy have worse health outcomes, but understanding the true impact of health literacy may require a detailed analysis of its effects on other known determinants of outcome. This study of 175 adult asthma patients in a primary care urban practice looked at the indirect effect of health literacy through independent variables, in addition to direct effects. Variables analyzed included demographic and asthma characteristics, depressive symptoms, knowledge of asthma and confidence in self-managing asthma when confronted with precipitants (self-efficacy). Health literacy was measured by means of questionnaires and the Test of Functional Health Literacy in Adults (TOFHLA).

Key Findings:

• Less health literacy was associated with worse asthma-related quality of life, worse physical function and more emergency department use over a period of two years.
• Health literacy continued to impact outcomes through its effects on other variables, particularly knowledge of asthma.
• Strong associations existed between health literacy and both depressive symptoms and resource utilization (increased use of emergency departments for asthma care).
• Health literacy was not associated with self-efficacy, perhaps because it may be primarily experience based, not instruction based.

These findings suggest that efforts to improve asthma outcomes should focus on improving literacy skills that are required to learn, understand and implement effective self-management. Results of this study may not apply to other settings or to an older patient population, however, and further research is needed to build on these preliminary findings.