Duncan here: If you listened to Morning Edition this morning you
would have heard an absolutely gushing piece of news about the use of
statins (specifically, Crestor) and reduction of heart attacks and
strokes in people with low cholesterol. Now if you just like your
news to be almost completely positive then go here:
http://www.npr.org/templates/story/story.php?storyId=96941206
If you would like a more skeptical view that analyzes the actual
statistics and raises a few questions about taking Crestor at $1200
for the rest of your life, then read below. It is a piece written by
Maggie Mahar author of Money-Driven Medicine and Bull Market as well
as head honcho at the Health Beat Blog.
November 10, 2008
Advice for the “Seemingly Healthy”: Know Your Chances (Part I)
Here we go again. If you haven’t yet heard the news from the American Heart Association meeting that was held in New Orleans yesterday, here is Bloomberg’s report on a medical breakthrough that, some say, will “change the way we practice medicine.”
Bloomberg, Nov. 9: “AstraZeneca Plc's Crestor [a cholesterol-lowering medication] slashed the risk of heart attack, stroke and death by nearly half in people with normal or low cholesterol in a study, potentially opening a way to save the lives of thousands of seemingly healthy people.”
I like that last phrase: “seemingly healthy people.” As we all know, there are no truly healthy people. Even if you think you might be healthy—you’re worried. You know there is probably something wrong with you.
Here, I can’t help but think of “The Last Well Person.” This was the title of an “Occasional Note” that Tennessee physician Clifton Meader wrote for The New England Journal of Medicine in 1994. His fiction was set in the not-too-distant future, and focuses on a 53-year-old professor of freshman algebra at a small college somewhere in the Midwest. He is…you guessed it, the very last healthy American. Using advanced medical screening, physicians have found something wrong with everyone else.
Now medical science is catching up with Meader’s science fiction. It’s beginning to look as if all of should be taking Crestor, or some other cholesterol-lowering drug (a.k.a. a statin) even if we don’t have high cholesterol.
The trial of Crestor reported at the AHA conference yesterday, showed the effect of the drug on patients who did not suffer from high levels of “bad” cholesterol—but did show high levels of a protein called CRP. It turns out that CRP is a marker for inflammation. It is tied to heart risk even in “well” people with no additional symptoms. At the moment, Crestor is approved by U.S. regulators only to lower bad cholesterol. Now, it appears that it also reduces inflammation, and other statins may have the same effect.
As a result, some experts say the study supports broad use of a high-sensitivity CRP test to find people who may be falsely assured by low cholesterol levels that they are protected from trouble. High-sensitivity CRP tests are available just like cholesterol lab tests, and some insurers will cover the cost.
Bloomberg cannot help but gush: if enough people are tested, the news “may help double Crestor's yearly sales to $6.33 billion by 2015, expand the $34 billion market for all cholesterol-lowering medicine and prevent 50,000 heart complications a year, analysts and doctors said. The results suggest an additional 6 million men over age 50 and woman over age 60, the group studied, should take the drugs.
“‘Half of heart attacks and strokes happen among apparently healthy men and women with normal or even low levels of cholesterol,’” observes Paul Ridker, the lead investigator from Harvard Medical School in Boston. “‘We as physicians simply cannot assume our patients are at low risk just because they have low cholesterol.’”
There you go. Just because you look healthy and feel healthy doesn’t mean you are healthy. (Ridker, by the way, holds a "use patent" on CRP testing for heart disease risk. According to NPR, “he says the patent hasn't affected his judgment and that the data speaks for itself.”)
Ridker’s statement reminds me of an ad from New York City’s Memorial Sloan Kettering Hospital that ran in the New York Times :
The early warning signs
of colon cancer
~~~~~~~~~~~~~~~~~~~~~~
You Feel Great
You Have a Healthy Appetite
You’re Only 50.
Drs. Steve Woloshin, Lisa Schwartz and H. Gilbert Welch reproduce this ad at the very beginning of their excellent new book: Know Your Chances: Understanding Health Statistics (How To See Through the Hype in Medical News, Ads and Public Service Announcements).
They use the ad (which looks like a tombstone) to illustrate how health care advertising can leave you “with an exaggerated sense of risk” The ad “says that you need to worry: if you feel well, you may have colon cancer.”
Then there is this message: “Colon Cancer will strike about 150,000 Americans.” Of course, to make sense of this statement, you need to ask “150,000 out of how many?” The answer is 150,000 out of 300 million—or just 0.5 percent of the population.
Putting the Numbers in Context
Know Your Chances is all about putting the numbers describing risks and benefits in context. And this is what Americans need to do when they hear the news stories about Crestor. Should everyone be tested for CRP? If it turns out your CRP levels are high should you start downing Crestor, “just to be safe? “
In an editorial in the current issue of the New England Journal of Medicine, Mark Hlatky, a professor of medicine at Stanford University takes a closer look at the Cresetor study. On the one hand, “The relative risk reductions achieved with the use of statin therapy in [the study] were clearly significant,” Hlatky writes. In other words, when you compare the placebo group to the group that took the medication, you find that the percentage who suffered “hard cardiac events” was indeed cut in half.
But then he goes on to examine “absolute differences” in risk—which involves looking at the actual number of people who benefited, while also considering the possible side effects and other costs of taking the medication. When you put the numbers in that context, you find that the risk/benefit equation looks quite different.
First, while the headlines tell you that the drug slashed the combined number of heart attacks , strokes and deaths in half—what that really means is that the number who suffered one of these “adverse events” was pared from 1.8% (157 out of 8901 patients who received a placebo) to .9% (83 of the 8901 patients who took Crestor).
Hlatky sums up the medical miracle: “120 participants were treated for 1.9 years to prevent one event.” 120—that’s the number of subject researchers needed to treat in order to spare one person a stroke or a heart attack. (Note, not all adverse events led to death.) For more on “number needed to treat,” to find one patient who benefits, see Niko’s excellent post here on Health Beat.
Here is the question you have to ask yourself: would you want to take this drug for the rest of your life based on the possibility that you might be the 1 out of 120 who benefits? It depends.
First, it depends on how you feel about the side effects. The patients who took Crestor showed “significantly higher glycated hemoglobin levels and incidence of diabetes,” Hlatky points out (3.0%, vs. 2.4% in the placebo group). Translation: There were 270 cases of diabetes among patients who took Crestor compared with 216 among those on placebo.
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