Assessing Health Literacy in Clinical Practice

Abstract

Health literacy is the ability to obtain, process, and understand health information and to use that information to make appropriate decisions about one's health and medical care. Large-scale national surveys conducted by the US Department of Education indicate that about one third of the American adult population (90 million Americans) has limited health literacy. People with limited health literacy have less health knowledge, worse health status, and higher healthcare costs than individuals with adequate health literacy -- even after controlling for potentially confounding sociodemographic factors.

Clinicians routinely underestimate the prevalence of limited health literacy among their patients and frequently overestimate the ability of individual patients to understand the information they provide to those patients. Awareness of the prevalence of limited health literacy in a clinician's practice, however, can allow the clinician to modify communication methods to match the needs of patients.

To learn the prevalence of limited health literacy in their practices, clinicians can use one of several instruments to assess the health literacy skills of a sample of their patients. These instruments are easy to use. Some take only 2 to 3 minutes, and English and Spanish versions are available. Use of these instruments is well accepted by patients.

Defining Health Literacy

Health literacy is the ability to obtain, process, and understand health information and use that information to make appropriate decisions about one's health and medical care. ^[1] Health literacy is closely related to general literacy -- the ability to read, write, and understand numbers -- but refers more specifically to information in a healthcare context.

Individuals with good health literacy skills will be able to obtain and use health information through (a) reading and comprehending text; (b) understanding documents that contain tables, graphs, and forms; and (c) understanding basic mathematical concepts. Unfortunately, current data indicate that nearly 90 million Americans (more than one third of the adult population) have limited health literacy.

The large number of people with limited health literacy has important implications for health providers and the American health system. The implications are so important that the problem of limited health literacy has been the focus of recent reports from the Institute of Medicine, ^[1] the Agency for Healthcare Quality and Research, ^[2] the Joint Commission, ^[3] and the American Medical Association. ^[4]

Prevalence of Limited Health Literacy

Once every decade, the US Department of Education conducts a nationwide study of the literacy skills of American adults. The most recent assessment, called the National Assessment of Adult Literacy (NAAL), was completed in 2003. ^[5] In addition to assessing general literacy, the NAAL also specifically assessed health literacy.

NAAL involved in-person interviews with nearly 20,000 Americans aged 16 years and older. NAAL participants were selected through a stratified sampling technique to represent the sociodemographic characteristics and geographic distribution of the entire US population. Interviews took place in private in participants' homes or, in the case of prisoners, in a classroom or library. The interviews involved a comprehensive assessment of participants' ability to read text, understand forms and documents, and use numbers.

Limited Health Literacy in the American Population

Based on their ability to successfully complete tasks posed by the NAAL assessment, the health literacy skills of participants were divided into 4 skill levels, termed "proficient," "intermediate," "basic," and "below basic." Examples of tasks at each of these skill levels are shown in Table 1.

Table 1. Sample Health Literacy Tasks From the National Assessment of Adult Literacy

Information from: Kutner M, Greenberg E, Jin Y, Paulsen C. The Health Literacy of America's Adults: Results from the 2003 National Assessment of Adult Literacy (NCES 2006-483). Washington, DC: National Center for Education Statistics, US Department of Education; 2006.

NAAL data indicate that only 12% of the American adult population has proficient health literacy skills (Figure 1). These individuals can deal with complex and challenging health literacy tasks. An additional 53% has intermediate skills, meaning they can deal with most health literacy tasks they encounter.

Figure 1. Health literacy skill levels of the American adult population. From: Kutner M, Greenberg E, Jin Y, Paulsen C. The Health Literacy of America's Adults: Results from the 2003 National Assessment of Adult Literacy (NCES 2006-483). Washington, DC: National Center for Education Statistics, US Department of Education; 2006.

The remainder of the population, however, has either basic skills (22%) or skills below the basic level (14%). These individuals with basic or below-basic skills total nearly 90 million Americans, or 36% of the adult population, and they are considered to have inadequate health literacy. People with basic or below-basic health literacy are not able to reliably obtain, understand, and use health-related information to make appropriate and informed decisions about their health and medical care. Indeed, many of these individuals have only rudimentary reading skills, and they frequently do not understand what clinicians tell them, nor can they read handouts and other written information provided to them by healthcare providers.

Copyright 2007: American Medical Association and American Medical Association Foundation