Interventions to improve health outcomes for patients with low literacy. A systematic review

To perform a systematic review of interventions designed to improve health outcomes for persons with low literacy skills.

We searched MEDLINE, Cumulative Index to Nursing and Allied Health (CINAHL), Educational Resources Information Center (ERIC), Public Affairs Information Service (PAIS), Industrial and Labor Relations Review (ILLR), PsycInfo, and Ageline from 1980 to 2003.

We included controlled and uncontrolled trials that measured literacy and examined the effect of interventions for people with low literacy on health outcomes, including health knowledge, health behaviors, use of health care resources, intermediate markers of disease status, and measures of morbidity or mortality. Two abstractors reviewed each study for inclusion. Disagreements were resolved by consensus among the research team.

One reviewer abstracted data from each article into an evidence table; the second reviewer checked each entry. Disagreements about information in evidence tables were resolved by team consensus. Both data extractors independently completed an 11-item quality scale for each article; scores were averaged to give a final measure of article quality.

We identified 20 articles examining interventions designed to improve health among people with low literacy. The most common outcome studied was health knowledge; fewer studies examined health behaviors, intermediate markers, or measures of disease prevalence or severity. The effectiveness of interventions appeared mixed. Limitations in research quality and heterogeneity in outcome measures make drawing firm conclusions about effective strategies difficult. Only 5 articles examined the interaction between literacy level and the effect of the intervention; they also found mixed results.

Several interventions have been developed to improve health for people with low literacy. Limitations in study design, interventions tested, and outcomes assessed make drawing conclusions about effectiveness difficult. Further research is required to understand better the types of interventions that are most effective and efficient for overcoming literacy-related barriers to good health.