Patients’ Health Literacy Skills: The Missing Demographic Variable in Primary Care Research

Health literacy has been defined as the ability to obtain, process, and understand basic information and services needed to make appropriate health decisions.¹ According to a recent report from the Institute of Medicine, Health Literacy: A Prescription to End Confusion, almost one half of Americans have difficulty understanding basic health information.² Although limited educational attainment, generally less than a high school or general equivalency diploma, has been long recognized as a strong risk factor for poor health status and greater likelihood of less-healthful behaviors, the link between health literacy skills and health-related outcomes is even stronger.

Research during the past 15 years has shown that those with limited health literacy skills have higher health care costs, use health care services more frequently, have poor understanding of chronic disease management techniques, underuse preventive health services, engage in riskier health behaviors, and tend to be less knowledgeable about health-related topics than those with adequate health literacy skills.² Based on these findings, primary care investigators should carefully consider including patients’ health literacy skills as a key demographic variable when conceptualizing their research studies.

Two types of standardized literacy assessment tools—word recognition tests and reading comprehension tests—have been widely used to measure patients’ literacy skills. Although several literacy assessment tools are available, the Rapid Estimate of Adult Literacy in Medicine (REALM)³ and Test of Functional Health Literacy in Adults (TOFHLA)⁴ were developed specifically to measure patients’ health literacy skills. The REALM and TOFHLA are valid and reliable, and they can be easily administered while gathering demographic information from patients.

The REALM, the mostly commonly used tool, takes less than 5 minutes to administer and score. The REALM is a word-recognition test comprising 66 medical terms, arranged in order of complexity by the number of syllables and pronunciation difficulty, starting with simple one-syllable words (eg, pill, eye) and ending with multisyllable words (eg, antibiotics, potassium). Patients read down the list, pronouncing aloud as many words as they can while the examiner scores the number of words pronounced correctly using standard dictionary pronunciation as the scoring standard. Scores on the REALM vary from 0 (no words pronounced correctly) to 66 (all words pronounced correctly.) The score assigns health literacy skills into 4 categories of grade-equivalent reading level: 0–18 (≤3rd grade), 19–44 (4th to 6th grade), 45–60 (7th to 8th grade) and 61–66 (≥9th grade).

The TOFHLA and a short form of the TOFHLA (S-TOFHLA) are available in both English and Spanish. The TOFHLA takes approximately 22 minutes to administer, while the S-TOFHLA takes about 7 minutes. The TOFHLA and S-TOFHLA are timed reading comprehension tests that use the modified Cloze procedure, in which every 5th to 7th word in a passage is omitted and replaced with a blank space. The patient must select a word to fit into the blank spaces from the 4 multiple-choice options provided for each space. The TOFHLA is scored on a scale of 0 to 100, whereas the S-TOFHLA is scored on a scale of 0 to 36. Patients are categorized as having adequate health literacy if the TOFHLA score is 75–100, marginal health literacy if it is 60–74, and inadequate health literacy if the score is 0–59. Patients are categorized as having adequate health literacy if the S-TOFHLA score is 23–36, marginal health literacy if it is 17–22, and inadequate health literacy if the score is 0–16.

Patients with limited and marginal health literacy skills are routinely encountered in clinical settings.⁵ Although the field of health literacy is a relatively new area of inquiry, it is gaining momentum among investigators. We know that patients with limited health literacy skills face enormous obstacles navigating the health care system and struggle with tasks that many of us take for granted (eg, reading prescription bottles, calculating the amount of cough syrup to give to your child). The implication for adherence to treatment regimens and the threat to health outcomes are obvious and compelling. The time is now for primary care investigators to consider patients’ health literacy skills as a key variable in their research studies.