Assessment of online patient education materials designed for people with age-related macular degeneration

Health literacy is defined as the degree to which individuals have the capacity to obtain, cognitively process and understand health information to make informed health-related decisions [7]. Health literacy is demonstrated through skills in basic literacy when reading and understanding health information. Low health literacy is a significant problem in the U.S. [8] According to the American Medical Association (AMA), over one-third of American adults, approximately 89 million people, have inadequate health literacy [9]. Health literacy is the single best predictor of health outcomes [9, 10].

According to Legge, there are two reasons why reading comprehension may be poorer in people with low vision [11]. First, slower reading speed makes it difficult to maintain attention on text and integrate meaning across words and phrases. Second, the increased demands of decoding (i.e., translating print into words) and poorer quality of visual input may limit understanding. The readability and suitability of reading materials are additional factors that may impact reading performance in people with AMD. Readability is a quantitative assessment of the reading skills required to easily comprehend written material [10]. Readability is calculated by applying a mathematical formula to a sample passage of written text. A grade level (i.e., number of years of education needed to comprehend written text) is produced based on the number of syllables, words and sentences. Several formulas are used to assess readability; however, there is no consensus as to which formula is best to assess the readability of PEMs. The suitability (i.e., appropriateness) of written information is another important factor impacting comprehension of written health information [12]. For people with AMD, factors related to the layout and design of written information may support, or limit, comprehension of PEMs [11].

In 2016, the Program for the International Assessment of Adult Competencies (PIAAC) published the most current indicator of basic skills in literacy, numeracy and problem solving skills of American adults [13]. The PIAAC defines literacy as the ability to understand, evaluate, use and engage with written texts to participate in society, to achieve one’s goals and to develop one’s knowledge and potential. Findings from the survey indicated only 12% of American adults had proficient literacy skills. These results matched findings from the 2003 National Assessment of Adult Literacy (NAAL) survey which also found 12% of adult Americans had proficient health literacy skills to fully participate in the self-management of their own health [14]. According to the Centers for Disease Control and Prevention, people with low literacy are more likely to report poor health outcomes [15].

Comprehension of written health information is influenced by several factors including the ability to read text, locate and use written information in documents, and to use numbers embedded in print materials [16]. According to the Pfizer Principles for Clear Health Communication, health outcomes are impacted by low health literacy in two ways: (1) a mismatch between reading abilities and the reading level of written health information; and (2) lack of health-related information that is easy to understand [8]. Existing research indicates the impact of vision loss on health outcomes is often underestimated by health care providers [17, 18]. Health care providers who provide written PEMs must recognize how poor reading proficiency creates barriers to functional health literacy [19, 20].

The Center for Studying Health System Change reports 75% of physicians provide written PEMs on a routine basis [21]. Existing research has identified a discrepancy between PEM readability and the average American adult’s capacity to comprehend written health-related information [10, 22, 23]. Most PEMs are written at, or above, the tenth grade reading level and include written information too advanced for most patients to understand [24, 25]. On average, American adults read between the eighth and ninth grade level [14]. The gap is even wider for older adults. According to the United States Government Accountability Office, the average Medicare recipient reads at, or below, the fifth grade reading level [26]. The barriers to reading created by central vision loss put older adults with AMD at greater risk for low health literacy [14, 27]. To reach the needs of the largest range of adults, the AMA recommends health-related patient information be written below the sixth grade reading level [9]. For people with low literacy skills, the National Institutes of Health (NIH) Clear Communication Campaign suggests writing between the third and sixth grade reading level [28].

The internet has become the most widely accessible source of PEMs [29, 30]. A study by the Pew Internet and American Life Project found that 80% of American adults who use the internet have searched for online health information [31]. Although it has become easier to access PEMs online, most American adults are unable to process or understand the technical information within them to inform health-related decision making [29]. Determining whether existing PEMs meet the recommended guidelines for readability and suitability is a necessary first step for promoting health literacy and patient outcomes. This purpose of this study was to assess the general readability and suitability of online PEMs designed for people with AMD. This research is needed to determine if existing online PEMs are appropriate (i.e., readable and suitable) for this population, who is at greater risk for low health literacy [14, 27].

Existing research has explored the readability of PEMs across a variety of health conditions and subspecialties [10, 22, 23, 32‐35]. A major gap in the literature exists surrounding treating people with AMD as a unique group under the larger umbrella of low vision [36]. A handful of studies have explored the readability of online PEMs for a range of different ophthalmic diagnoses [30, 37‐39]. None of these studies have explored the readability of PEMs designed for people with AMD. The suitability (i.e., appropriateness) of PEMs is also important when determining the fit between written health-related information and the reading capacities of a target population. To date, this is the first study to focus solely on the readability and suitability of online PEMs designed for people with AMD. This study is needed to fuel future research and develop population-specific PEMs that meet the unique learning needs of this population.

The purpose of this study is to determine the general readability and suitability of online PEMs designed for people with AMD. Furthermore, this study aims to identify the percentage of online PEMs that achieve the national guidelines for readability level (≤ sixth grade) and the recommended suitability score (≥ 70%). The researchers hypothesize that the majority of online PEMs designed for people with AMD will be written at grade levels above the recommended readability level, and below the recommended suitability score. To date, this is the first study to assess the readability and suitability of online PEMs designed specifically for people with AMD.

This study was approved by the Institutional Review Board at Western Michigan University. A convenience sample of online PEMs was sourced from websites of professional organizations who provide patient education on AMD (Table 1). The primary researcher consulted with two occupational therapists specializing in low vision rehabilitation to identify credible sources of educational information. The target sample size for this study was 100 PEMs. To locate PEMs, the key words “age related macular degeneration (AMD)” were entered into the search engines of each organization’s website. If a search engine was not available, the primary researcher searched the website manually. To be included in the sample, PEMs had to meet the following inclusion criteria: (1) written by a professional society or clinical practice website; (2) published in English; (3) contain patient education designed for people with AMD. Scientific articles, opinion pieces, patient forums and PEMs about similar topics (e.g., low vision and Stargardt disease) were excluded from this study.

One-hundred online PEMs were randomly selected from the websites of organizations providing patient education designed for people with AMD. The primary researcher determined the general readability and suitability of each individual PEM, as well as the percentage of PEMs that achieve the recommended readability (≤ sixth grade level) and suitability score (≥ 70%). Written text from each PEM was copied from the website and pasted into a Microsoft Word document [40]. To improve the accuracy of readability calculations, the text was cleaned prior to analysis. The process included removing all unrelated material such as copyright notices, disclaimers, date stamps, graphics, tables, author information, hyperlinks, in-text citations and reference lists. To achieve a uniform style, each passage of text was highlighted and “right-clicked” to access the “clear formatting” option. Next, bullets, paragraph breaks and some punctuation (e.g., quotation marks, parentheses, colons and semicolons) were removed. A period was added after each heading, sentence fragment or sentence. Numbers, decimals and percentages were converted to written form (e.g., “2.5%” was converted to “two point five percent”). To improve the accuracy of word count, dashes were removed and compound words were separated into root words (e.g., “age-related” was changed to “age related”).

There are over 40 readability indices available to calculate the grade level of written text [41]. Each index utilizes a mathematical formula based on the number of syllables, complex words and sentences. Opinions vary as to which index is the most accurate; however, several readability formulas are used in health care settings [10]. The Flesch-Kincaid Grade Level (FKGL) formula measures readability of written text using the average sentence length and syllables per word [42]. The FKGL is a widely used readability formula [43, 44]. For this study, readability was calculated using the FKGL formula embedded in Microsoft Word software. To enable this tool, the researcher selected the “Review, Spelling & Grammar” functions in sequential order. A readability level is displayed after the grammar and spell check process is complete. The FKGL formula was chosen for this study because it is quick and easy to administer, has been extensively validated, and correlates highly with other readability formulas [10]. To assess the reliability of the FKGL tool embedded into Microsoft Word, 10 clean passages of text were randomly selected and entered into a second FKGL readability calculator available online [45]. There was near perfect agreement between the two readability calculators. The mean errors were 0.17 grade levels between the Microsoft Word and online FKGL readability calculators.

When examining the match between the demands of written text and the capacities of the target audience, the impact of design characteristics on comprehension should also be considered. Factors such as graphics, layout and typography can be difficult to assess in an objective manner. The Suitability Assessment of Materials (SAM) instrument is a valid and reliable tool designed to assess the overall suitability (i.e., appropriateness) of health information for a specific audience [41]. The SAM has been administered successfully in previous research on health literacy [46‐48]. For this study, the SAM instrument was used to measure the suitability of PEMs across six categories: (1) content; (2) literacy demand; (3) graphics; (4) layout and typography; (5) learning stimulation; and (6) cultural appropriateness. A percentage score and suitability rating was calculated for each PEM based on the appropriateness of health information for people with AMD. Interpretation of SAM scores are as follows: 0–39% - Not Suitable; 40–69% - Adequate; and, 70–100% - Superior [40]. Based on scoring and interpretation methods described by the authors, a SAM percentage score ≥ 70% is needed for PEMs to be considered suitable in this study.

Statistical analysis was completed with IBM SPSS 25 software [49]. Descriptive statistics were used to determine mean FKGL and SAM scores and the percentage of online PEMs that achieved the national guidelines for readability level (≤ sixth grade) and recommended suitability score (≥ 70%).

This study has limitations. This study did not provide the opportunity for people with AMD to evaluate the true readability and suitability of the PEMs in the sample. Therefore, the findings lack confirmation from people with AMD. This study is limited because a single readability index (e.g., the FKGL) was used to calculate the readability of PEMs. Furthermore, the FKGL is not a direct measure of comprehensibility; therefore, there is a possibility the results of this study could underestimate the level of difficulty required to read health information. Although the results of this study show the mean readability of the PEMs included in this study are higher than the recommended guidelines, additional factors should be considered. For example, the words “age-related macular degeneration” are considered difficult to read simply based on the number of syllables involved. These words appeared frequently and cannot be replaced. These limitations may impact the generalizability of results to the greater population of people with AMD.

The existing guidelines for promoting health literacy do not consider how age and visual impairment may create additional barriers to processing and understanding of written health information. Future research should address the need for treating people with AMD as a unique group under the larger umbrella of low vision. Chung questions whether reading performance could be enhanced by modifying certain characteristics of text to better match the capabilities of the peripheral visual system [6]. Additional studies are needed to determine the optimal design and presentation of PEMs for this population. Future research should also evaluate the benefits of PEMs that have been modified based on established guidelines for patients with low health literacy and low vision.