My guess is that if you want to improve health outcomes in the United States, ignore health insurance and focus on literacy... This means that 90 million Americans can understand discharge instructions written only at a fifth-grade level or lower.
I wonder what explicit knowledge is constructed from the process of reading health information via the internet, doctor written instructions or as King wonders, discharge instructions. I don't think this is directly the cause, how influential is a written statement compared to immediate observations? A better perspective may be what is the path of least resistance for a person - how much additional learning is required - and how did that path get created? A more literate person's path is sharply different from a less literate, though maybe Frost was right, whichever path we pursue we'll be able to rationalize it just fine.