COMMENTARY Low Health Literacy: Epidemiology and Interventions Darren A. DeWalt, MD, MPH ealth literacy entered the mainstream medical literature the problems associated with not reading well can help us identify in 1995 with an article published in the Journal of the key principles for addressing health literacy. H 1 American Medical Association . Since that time, we have The most up-to-date portrait of reading ability in the witnessed the emergence of a field of research and advocacy United States was the 2003 National Assessment of Adult that attempts to improve health communication so that all Literacy (NAAL). 2 The NAAL found that 43% of adults read people can understand and act on health information. In this at basic or below basic levels. Based on analysis by economists commentary, I will review the epidemiology of low health and educators, people who read at these levels are not adequately literacy, our understanding of the relationship between literacy skilled to compete in the current economy or to effectively and health outcomes, and emerging interventions to mitigate negotiate much of the health care system. 3 This current state of the effects of low health literacy. As this field rapidly gains new affairs is astounding and should call close attention to how we insights, we are beginning to learn how to address the problem. provide health care. If close to half of the population we serve is unable to accurately participate in Epidemiology of Low health care, we need to fundamentally Health Literacy “If close to half restructure how we operate. As we pursue patient-centered care, we must Health literacy, as defined by of the population consider the information processing Healthy People 2010 and described skills of those we serve and adjust our in the issue brief in this issue of the we serve is unable actions to match the skill level. North Carolina Medical Journal , is a construct which has been elusive to Health Literacy and Health measure as a single variable. Most of to accurately Outcomes the research to date has focused on the ability to read basic health participate in The importance of health literacy is information. However, all of us can underscored by its relationship to health identify a friend or colleague who health care, we need outcomes. The research to date has has excellent reading skills, but who focused on the relationship between has low health literacy. This person to fundamentally reading ability and health outcomes, has trouble understanding and acting largely because reading ability is easier on health information. As such, restructure how we to measure than the broader concept describing the epidemiology of health of health literacy. Regardless, if poor literacy requires an explanation of operate.” reading ability translates to poor what has been traditionally measured health outcomes—after controlling in these studies. To date, researchers have measured reading ability for variables like insurance, income, race, ethnicity, and disease as a proxy for health literacy. Measuring reading ability emphasizes severity—then we are more confident that inability to understand the role of understanding written health information and would health information is an important factor for health outcomes. likely classify our colleague with excellent reading skills as having In 2004, the Agency for Healthcare Research and Quality “high health literacy.” So, although measuring reading ability (AHRQ) released a report on the relationship between literacy does not give us the full picture of health literacy, understanding and health outcomes. 4,5 This report found that, across several Darren A. DeWalt, MD, MPH , is an assistant professor of medicine in the Division of General Internal Medicine at the University of North Carolina School of Medicine. He can be reached at dewaltd (at) med.unc.edu or Campus Box 7110, Chapel Hill, NC 27599-7110. NC Med J September/October 2007, Volume 68, Number 5 327 areas of health and health care, low literacy was associated with that further study in this area could be promising. a worse prognosis than higher literacy even after controlling for What about the children? Unfortunately, approximately confounding variables. one-third of our nation’s children do not graduate from high Since the publication of the systematic review, several new school, a statistic that has not changed in 30 years. 19 As such, I articles have added to the evidence by evaluating new populations anticipate that the problem of low health literacy will remain and new outcomes. Two studies have documented that people with us in the foreseeable future. Expanding curricula in health with lower literacy die at a faster rate than people with higher literacy for primary and secondary education may help to literacy. 6,7 Patients with low literacy are more likely to familiarize students with the health care environment, but misunderstand prescription medication instructions and improving graduation rates may be more important for the warning labels. 8-10 Young children with asthma who have overall health of the population. parents with low literacy have more days of school missed and more hospitalizations. 11 The body of literature associating low 2. Improve Written and Multimedia Communication literacy with worse health outcomes becomes more robust each Most of the research and advocacy related to health literacy year. Some studies are beginning to explore potential mediating has focused on written and multimedia communication. variables such as self-efficacy, 12,13 medication knowledge, 10,14,15 Numerous studies have shown that the readability of health and patient-physician communication. 16 As we begin to information almost always exceeds the reading ability of its understand the mediators between literacy and health outcomes, intended audience. If we (health care professionals) were a our intervention design will become more informed and effective. communications agency, we would be fired. Creating better written messages and using other forms of media (audio or Interventions to Mitigate the Effects of Low video) have been tested in clinical research and can improve Health Literacy knowledge. 5 Written messages targeting specific illnesses can increase the rate of physician-patient dialogue on a topic and Interventions to mitigate low health literacy usually fall into increase the receipt of clinical preventive services. 20,21 Creating one of 4 categories: health messages that are understandable by most of the intended audience is an imperative for any systematic approach toward (1) Improve health literacy skills in the population addressing low health literacy. Experts have developed guides (2) Improve written and multimedia communication for creating health messages, 22 and more and more examples are (3) Improve patient-provider communication in health care published in the medical literature. 23-25 visits Beyond improving specific patient education materials, we (4) Alter systems of care need to consider broad-based campaigns to activate people to ask questions and seek clarity. Such campaigns have been created No doubt, such a framework is an oversimplification, but it including the Justus-Warren Heart Disease and Stroke Task lays out what we need to think about when addressing health Force message “Start with Your Heart” 26 and the AHRQ funded literacy at the state level. I will briefly review each category and message “Questions Are the Answer: Get More Involved With the current state of knowledge for each. Your Health Care.” 27 Although we do not know how much effect these messages have had, they normalize the behavior of 1. Improve Health Literacy Skills in the Population seeking clarity in the health care setting. Such social marketing Although the most attractive solution, this may be the most approaches may lead to more efficacious health care encounters. elusive. Improving the reading ability of an adult takes hours of personalized instruction and self-motivation. With one year of 3. Improve Oral Communication in Health Care Visits intense adult basic education, a person’s reading level increases Health communication researchers have known for years about one or two grade levels. Such improvements, if targeting that patients remember about 50% of what they are told in a germane topics, may improve function in the health care visit with a physician. 28 Even that which is remembered is often environment, but educating 90 million adults with such remembered incorrectly. 29 This is especially of concern when specificity and intensity is not feasible. No studies have been most health communication takes place orally in the health care published that demonstrate improved health literacy over time. setting. Therefore, strategies that improve oral communication As such, we do not know if specific health-related information may lead to better health outcomes, particularly for those with processing can be improved faster than general reading ability. low health literacy. We have a small amount of evidence that literacy training People who have strong reading and information processing programs can improve depression outcomes, regardless of the skills can get by in the current environment because they can improvement in literacy. Two studies have enrolled people in seek more information after they leave the health care setting adult literacy courses, and both showed an improvement in by looking on the Internet or in books. Unfortunately, a large depression symptoms when compared to a control group. 17,18 part of society cannot access information so easily and must The mechanism of the effect may be related to self-confidence rely on good information transfer in the clinic or hospital. and life skills improvement for people who have been struggling Although an important area of research, we do not have much to get by. Regardless of the mechanism, the outcome suggests empirical evidence on what strategies work best. 328 NC Med J September/October 2007, Volume 68, Number 5 The most promising strategy to facilitate understanding in One system in North Carolina created a diabetes disease the office setting is the teach-back method.