Context: Patients with limited literacy are at higher risk for poor health outcomes; however, physicians' perceptions are inaccurate for identifying these patients.
Objective: To systematically review the accuracy of brief instruments for identifying patients with limited literacy.
Data sources: Search of the English-language literature from 1969 through February 2010 using PubMed, Psychinfo, and bibliographies of selected manuscripts for articles on health literacy, numeracy, reading ability, and reading skill.
Study selection: Prospective studies including adult patients 18 years or older that evaluated a brief instrument for identifying limited literacy in a health care setting compared with an accepted literacy reference standard.
Data extraction: Studies were evaluated independently by 2 reviewers who each abstracted information and assigned an overall quality rating. Disagreements were adjudicated by a third reviewer.
Data synthesis: Ten studies using 6 different instruments met inclusion criteria. Among multi-item measures, the Newest Vital Sign (English) performed moderately well for identifying limited literacy based on 3 studies. Among the single-item questions, asking about a patient's use of a surrogate reader, confidence filling out medical forms, and self-rated reading ability performed moderately well in identifying patients with inadequate or marginal literacy. Asking a patient, "How confident are you in filling out medical forms by yourself?" is associated with a summary likelihood ratio (LR) for limited literacy of 5.0 (95% confidence interval [CI], 3.8-6.4) for an answer of "a little confident" or "not at all confident"; a summary LR of 2.2 (95% CI, 1.5-3.3) for "somewhat confident"; and a summary LR of 0.44 (95% CI, 0.24-0.82) for "quite a bit" or "extremely confident."
Conclusion: Several single-item questions, including use of a surrogate reader and confidence with medical forms, were moderately effective for quickly identifying patients with limited literacy.