Medical News Stories: Beware Of Insufficient Evidence
After seeing the NBC Nightly News last night, a physician urged me to write about what he saw: a story about a “simple blood test that could save women’s lives.”
Readers – and maybe especially TV viewers – beware whenever you hear a story about “a simple blood test.”
And this is a good case in point.
Brian Williams led into the story stating:
“Two of three women who die suddenly of cardiac heart disease have no previous symptoms which is all the more reason women may want to ask their doctors about a blood test that can be a lifesaver.”
Then NBC News chief medical editor Dr. Nancy Snyderman said:
“It’s not a new test, it’s not an experimental test but nonetheless it’s a test not a lot of people know about and that’s a problem because this simple blood test could save your life.”
The test in question is the C-reactive protein or CRP test.
We’re only seconds deep into the story and “lifesaver” or “save your life” have come up twice. We’ll hold our breath for the evidence to back that up.
Then the story profiles a woman at high risk of heart attack, but quickly transitions to stating that unspecified numbers of women who are told they’re at low risk are clearly at high risk. A doctor interviewed says:
“All too often we see people who were told they were at low risk for heart disease but they’re in the emergency room having a heart attack and so they’re clearly not low risk.”
And, Dr. Nancy says….
“… that’s because most doctors do not check for c-reactive protein for fear of overtreating them.”
That’s quite a leap: women are having heart attacks in the ER because doctors didn’t check them for CRP.
NBC’s choice of expert interviewee is Dr. Paul Ridker, who says:
“We have learned that the cost of the screening and the cost of the medication is quite small compared to the number of events prevented so it’s a win-win for everyone involved.”
NBC didn’t point out what others – such as Merrill Goozner and ethicist Howard Brody have – that another way of looking at the win-win is by looking at who holds the patent on the CRP test and who benefits from its use.
Goozner wrote several years ago:
“What if I told you Dr. Paul Ridker of Harvard owns the patent to using C-reactive protein as a biomarker of heart disease and it’s licensed to companies making the test. And what if I told you his research has been funded by drug companies that make statins, which lower cholesterol and may be used to combat high levels of C-reactive protein.”
Harvard’s Dr. John Abramson wrote to journalists in Nieman Reports:
“The commercial bias does not stop with the research, but affects the way the results are reported to the public as well.”
But we didn’t hear anything about financial conflict of interest in NBC’s story. Only this ending from Dr. Nancy:
“If you’re over the age of 40, this is the time to have a conversation with your doctor about this very simple blood test that’s covered by most insurance.”
Any woman over the age of 40? That’s quite a leap from the high-risk woman profiled in the piece.
The discussion of the evidence never came, did it?
Well, here it is, from the US Preventive Services Task Force:
“The U.S. Preventive Services Task Force concludes that the current evidence is insufficient to assess the balance of benefits and harms of using the nontraditional risk factors (including CRP) to screen asymptomatic men and women with no history of coronary heart disease to prevent coronary heart disease events.
…
Although using CRP to screen men and women with intermediate coronary heart disease risk would reclassify some into the low-risk group and others into the high-risk group, the evidence is insufficient to determine the ultimate effect on the occurrence of coronary heart disease events and coronary heart disease-related deaths.”
Lifesaver?
Simple blood test?
Sounds a lot more complicated than what NBC reported.
*This blog post was originally published at Gary Schwitzer's HealthNewsReview Blog*
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