Tuesday, December 5, 2023
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An online calculator is available to help clinicians and healthcare administrators estimate the prevalence of limited health literacy in their patient population. [67] The user enters data about the demographics of the population, such as the percentage of patients who are over 65 years of age, enrolled in Medicaid, and members of different racial/ethnic groups, and the calculator then computes a minimum estimate of the percentage of patients in that population likely to have limited health literacy. The calculator does not, however, provide information about the health literacy skills of individual patients.
For determining the literacy skills of individual patients, health literacy researchers have developed instruments that can be used to screen for limited health literacy or specifically measure health literacy levels. Some of these instruments take only 2 to 3 minutes to administer and are thus suitable for use in busy clinical settings. Others are more complex and used primarily for research.
The 3 most widely used instruments are the Newest Vital Sign (NVS), the Rapid Estimate of Adult Literacy in Medicine (REALM), and the Test of Functional Health Literacy in Adults (TOFHLA). These and several other approaches to health literacy assessment are discussed here.
The NVS is a tool used to screen for limited health literacy. The instrument is available in English and Spanish, and patients typically complete the NVS assessment in about 3 minutes. [68] Patients find the instrument acceptable as part of standard medical care, with more than 98% of patients agreeing to undergo the assessment during a routine office visit. [69] The NVS can be obtained online at no cost from the Partnership for Clear Health Communication.
The NVS presents patients with a nutrition label (from a container of ice cream) specifically designed and tested as part of NVS development (Figure 5). The examiner asks the patient 6 questions about the content on the nutrition label. Answering the questions correctly requires the ability both to read and understand the content on the nutrition label (eg, to determine if the list of ingredients on the ice cream label contains a substance to which the patient is allergic) and also to perform computations (eg, numeracy to calculate the number of calories in a serving of ice cream).
Figure 5. Nutrition label used in the Newest Vital Sign health literacy assessment (English version). Courtesy of Pfizer, Inc.
The patient's response to each of the questions is scored as correct or incorrect. One point is assigned for each correct answer, yielding a score that can range from 0 to 6. Patients who score 4 to 6 are classified as having adequate health literacy skills. Those who score 2 to 3 are classified as "possibly" having low health literacy, and those with a score of 0 to1 are classified as "likely" having low health literacy. The sensitivity and specificity of the NVS's English and Spanish versions are shown in Table 3.
Table 3. Performance Characteristics of the Newest Vital Sign for Detecting Limited Health Literacy
| Version | Score | Sensitivity | Specificity | Likelihood Ratio |
|---|---|---|---|---|
| English | 0-1 | 72% | 87% | 5.4 |
| Â | 2-3 | 100% | 64% | 1.2 |
| Â | 4-6 | - | - | 0 |
| Spanish | 0-1 | 77% | 57% | 1.8 |
| Â | 2-3 | 100% | 19% | 0.6 |
| Â | 4-6 | - | - | 0 |
Data from: Weiss BD, Mays MZ, Martz W, et al. Quick assessment of literacy in primary care: the Newest Vital Sign. Ann Fam Med. 2005;3:514-522.
The REALM is one of the oldest and most widely used health literacy assessment instruments. [70] Like the NVS, the REALM can be administered in about 3 minutes. The REALM is only available in English.
The REALM is a word-recognition test, in which patients are presented with a list of 66 medical words (Figure 6) beginning with easy words (eg, fat, flu, pill) and progressing to more difficult words (eg, osteoporosis, impetigo, potassium). Patients are asked to read through the list and pronounce each word out loud. The examiner scores the patient on the number of words pronounced correctly. No attempt is made to determine if patients actually understand the meaning of the words.
Figure 6. Word recognition list used in the Rapid Estimate of Adult Literacy in Medicine. Reprinted with permission of Terry C. Davis, PhD.
The number of correctly pronounced words is then is used to assign a grade-equivalent reading level. Scores 0 to 44 indicate reading skills at or below the 6th grade level, scores from 45 to 60 represent skills at the 7th or 8th grade level, and scores above 60 indicate skills at the high-school level or higher. Because so many patient handouts and forms are written at the high-school level or higher, [29-37] patients with scores ≤ 60 are considered at risk for misunderstanding written information provided to them.
Several other "spin-off" versions of the REALM have recently been developed. One, the REALM-Teen, is specifically designed for use with adolescents. [71] It is similar to the original REALM both in length (66 words) and in its instructions for administration. Another new version, called the REALM-7, uses only 7 words from the original 66-word REALM word list. A single study, reported in an abstract of meeting proceedings, reported that the 7-word version performed similarly to the full 66-word REALM for categorizing the health literacy skills of patients. [72] Others have developed word recognition lists, similar in concept to the REALM, to screen for limited health literacy in other fields, such as dentistry. [73]
The TOFHLA is a more complex health literacy assessment instrument that is often considered the instrument of choice when a detailed evaluation of health literacy is needed for research purposes. [74] The TOFHLA is available in English and Spanish and in its full-length form requires 20 or more minutes for administration. A shortened version is also available that incorporates some aspects of the full instrument, and it can be completed in about 12 minutes. [75]
The full TOFHLA has 2 parts, each with different kinds of questions. The first part uses 17 multiple-choice questions that test a patient's ability to interpret documents and numbers (numeracy). For example, patients are presented with a variety of medication labels and asked about how many pills should be taken, when they should be taken in relation to time of day or meals, when prescriptions expire, and how many times they can be refilled. A sample item from the first part of the TOFHLA is shown in Figure 7.
Figure 7. Sample items from the Test of Functional Health Literacy in Adults (TOFHLA). Reprinted with permission. TOFHLA is available only from Peppercorn Books, at http://www.peppercornbooks.com/catalog/product_info.php?products_id=2514
The second part of the TOFHLA assesses reading comprehension. Patients are presented with 3 passages of text from which selected words have been deleted and replaced with blank spaces. Patients need to choose, from a list of options, the words that make the most sense if placed into the blank spaces. This approach, called the modified Cloze technique, is one of the best approaches for assessing reading comprehension. [76] The 3 passages of text deal with what meal or drink can be consumed prior to a procedure, an application for medical insurance coverage, and a surgical consent form. A portion of a passage of text from the second part of the TOFLHA is shown in Figure 7.
Scores on the TOFHLA classify patients as having limited, marginal, or adequate health literacy. The instrument has been used successfully in a variety of patient populations and in age groups ranging from adolescence to geriatrics.
The short version of the TOFHLA (S-TOFHLA) contains only 4 multiple-choice numeracy questions and 2 reading passages. The numeracy scores on the S-TOFHLA correspond moderately (Cronbach's alpha = 0.68) and the reading comprehension scores correspond highly (Cronbach's alpha = 0.97) to scores on the full-length TOFHLA.
Several other approaches to health literacy assessment have also been developed. Few have undergone extensive evaluation, and the extent of their use in practice is uncertain.
The Short Assessment of Health Literacy for Spanish Speaking Adults (SAHLSA) is a 50-item assessment that includes a word recognition test and a multiple-choice reading comprehension test. [77] Recently developed and designed for use with Spanish-speaking adults, scores on the SAHLSA correlate moderately with scores on the TOFHLA (r = 0.65).
The eHealth Literacy Scale (eHEALS) is an 8-item measure of consumers' knowledge, comfort, and perceived skills at using information technology to obtain health information from electronic sources. The instrument has only been validated with adolescents. [78]
The Nutrition Literacy Scale was designed to measure a patient's ability to comprehend nutrition information. Scores on the instrument have a modest correlation (r = 0.61) with the S-TOFHLA.
Several investigators have studied whether a single question directed to patients might successfully identify those with limited literacy. Results of this research are encouraging, though the performance of the various questions varies and some of the questions lack sensitivity.
One study evaluated several different questions with patients in the Veteran's Affairs healthcare system and found that "How often do you have someone help you read hospital materials?" had the best performance characteristics for identifying patients with limited health literacy. Using responses of "sometimes," "always," or "often" to indicate limited health literacy, the question demonstrated a sensitivity of 73% using scores on the S-TOFHLA as the comparison standard. [79]
Another study, also involving the patients in the Veteran's Affairs healthcare system, used a similar question: "How often do you need to have someone help you when you read instructions, pamphlets, or other written material from your doctor or pharmacy?" As in the prior study, patients who responded "sometimes," "often," or "always" were considered to have limited health literacy. In contrast to the prior study, however, in this study the sensitivity for identifying patients with limited health literacy (again using the S-TOFHLA as the comparison standard) was only 54%. [80]
A third study evaluated the question, "How confident are you filling out medical forms by yourself?" with patients in a university-based primary care practice. A response of "somewhat," "a little bit," or "not at all" had an 83% sensitivity and 65% specificity for identifying patients with an 8th-grade or lower reading level on the REALM. [81]
These studies indicate that it may be possible to identify many patients who have limited health literacy with a single question, and the brevity of this approach is appealing. However, the variability in both questions studied and the performance of these questions leaves some uncertainty about which question is best. More research is needed to determine if single-question screens can be successfully used in practice.
