Your Medical Mind_ How to Decide What Is Right for You - Jerome Groopman [7]
Because all of us are deeply influenced by stories, we must remember that they represent individual events. Anecdotes are single cases, what researchers term “the n of 1.” While the lives of people facing similar clinical dilemmas make a deep impression on us, they may or may not reflect the experience of the larger population. Stories can make real the risks and benefits of a treatment that might otherwise seem abstract—but they can also distort our vision by making the rare appear routine.
Statistics can often help put messages from stories into a larger context. Would Susan change her mind if she knew the statistics about high cholesterol and risk for cardiovascular disease that informed her doctor’s advice?
Understanding statistics about the risks and benefits of a treatment is called “health literacy.” It is an important skill because it enables us to grasp the scientific data about a therapy and make a more considered choice than we could possibly make using narratives alone. Susan’s doctor put it like this: “Let me explain why this medicine is so important for your health. By taking a statin pill, you’ll reduce your risk of a heart attack over the next ten years by as much as 30 percent.”
Even with all her doubts, Susan found this an impressive number. But her thoughts returned to the woman at church. She asked, “What about the side effects?”
The doctor replied. “As I said before, I don’t expect that you’ll have any problems at this low dose. The risk of side effects is very small. At most, a few percent of people have muscle pain. And even if you get this side effect, it almost always reverses when you stop the treatment.” The doctor trained her gaze on Susan. “The chance of side effects is nothing like the 30 percent benefit you get from taking the medication.” Susan promised her doctor she’d give this new information serious thought.
Surveys show that more than 60 percent of people search the Web for medical information, and that number is increasing all the time. When Susan entered “cholesterol treatment” into Google, more than sixteen million entries popped up. She scanned the list from the top. Some hits were guidelines from medical societies; other sites were from pharmaceutical companies and hospitals; and still others were patient blogs.
Over the course of many months, Susan continued to search for information, reading everything she could about cholesterol. She found a government-sponsored link—a site from the United States Department of Health and Human Services. What caught her eye was “Health Information for the Public.” There were numerous diseases listed, and Susan clicked on “Cholesterol.” The link offered a “10-Year Heart Attack Risk Calculator,” and she realized this was exactly what she wanted to know. Yes, her father was healthy all his life, but what was her own risk?
It was easy to input the requested information. She entered her age, total cholesterol number, and “good” cholesterol, HDL, from the laboratory sheet her doctor had handed her. No, she was not a smoker. Her blood pressure was fine, the upper number at 120. And she was on no medications. She then clicked on “Calculate Your 10-Year Risk” at the bottom of the display, and out popped the result. “Risk Score: 1%: Means 1 of 100 people with this level of risk will have a heart attack in the next 10 years.”
Susan sat back and stared at the screen. This means that ninetynine of one hundred people like me won’t have a heart attack in the next ten years, she told herself. She started to feel much better.
Using the Web site, Susan had found a key number in health literacy, her risk for disease without treatment. Statin treatment will reduce Susan’s risk for a heart attack by 30 percent. Now, let’s figure out what this means.
Without treatment, Susan’s risk for a heart attack was 1 in 100. If 1 in 100 women has a heart attack, that means 2 in 200 do, or 3 in 300. The statin treatment reduces risk by 30 percent, or about one-third.