Only 12 percent of adults have Proficient health literacy, according to the National Assessment of Adult Literacy.  In other words, nearly nine out of ten adults may lack the skills needed to manage their health and prevent disease.  Fourteen percent of adults (30 million people) have Below Basic health literacy.  These adults were more likely to report their health as poor (42 percent) and are more likely to lack health insurance (28 percent) than adults with Proficient health literacy.
Low literacy has been linked to poor health outcomes such as higher rates of hospitalization and less frequent use of preventive services. Both of these outcomes are associated with higher healthcare costs.