Recently in Risk communication Category

Two important studies on health care decision-making in the journal PLoS Medicine were nicely summarized by MedPage Today. Excerpts:

How doctors portray clinical risks and benefits -- statistically and visually -- can influence the decisions patients make about healthcare, and whether those decisions reflect their own values, two randomized studies found. ...

One study asked patients whether they would take statins to prevent coronary heart disease (CHD) at a cost of $50 a month, knowing the risks and benefits of taking the drugs.

They found that people were more likely to choose treatment when the data were presented as relative risk reduction -- for example, telling patients they would be 30% less likely to develop CHD by taking statins -- rather than as absolute summary measures.

However, far more participants believed their understanding of and satisfaction with risk information -- and their confidence in their decisions -- were greater when natural frequency data were presented.

It seems like every day on we hammer away at stories that give only relative risk data - not absolute risk data as well. This is really important stuff - as shown in these studies.

The editors of the journal commented:

"It is clear ... that there is the potential for shared decision-making to be biased through the adoption of more persuasive presentations -- such as relative statistics. As a result, the underlying principle of shared decision-making -- that of empowering patients to make decisions most compatible with their values -- can be undermined."

Old news, news releases & confidence intervals

Dr. Len's Cancer Blog, written by Dr. Len Lichtenfeld, Deputy Chief Medical Officer of the American Cancer Society, offers a terrific example of how to scrutinize confidence intervals in a study.

He commented on a study that got a lot of news coverage - suggesting that women with breast cancer who took tamoxifen had 440% greater chance of developing a more aggressive, hormone insensitive tumor compared to women who did not take the drug. He then jumped in with a lesson:

In statistics, there is something we call the "confidence interval." In simple terms, it means if you kept repeating the same experiment in different populations or with more women in the same population, what is the chance you would come up with the same result? What are the possible other numbers that may show up?

Sitting down?

In this study, the confidence intervals for that 440% number vary from 1.03 (a 3% increased risk) up to 19 (a 1900% risk). In our world, that is what we call "not very tight." That 1.03 number--in reality--just gets you over the line of what we call statistical significance.

He had other problems with the way the news of the study was disseminated. Read his entire thoughtful blog posting.

(Thanks to Ivan Oransky for pointing out Dr. Len's posting.)

On-air spat between anchor and medical correspondent


Dr. Nancy Snyderman of NBC News appeared on the Today Show with Matt Lauer last week, profiling a physician-author who has written that the best science does not establish a causal link between childhood vaccines and autism. Matt & Nancy.png

Lauer, in a followup question, mis-spoke and called it a "casual" link - not causal. One wonders whether he truly knows what the words mean.

Snyderman talked about how the physician-author, Dr. Paul Offit (author of "Autism's False Prophets"), has received death threats. Snyderman herself said she had been physically ambushed by those who contend that vaccines cause autism.

As Snyderman was wrapping up the segment, Lauer said - in typical anchor throwaway language:
"Controversial subject ..."

Snyderman immediately shot back, "Not controversial subject , Matt. ...It's time for kids to get vaccinated. The science is the science. It's not controversial."

You can see the video here or here.

Kudos to Snyderman for educating her big-bucks anchor colleague live on-the-air.

Young men and prostate cancer screening

Just a week after the U.S. Preventive Services Task Force published new recommendations questioning the use of the PSA blood test in even more men, a new survey suggests that many young men are getting the test.

HealthDay News reports:

One in five men in their 40s has had a prostate-specific antigen (PSA) test in the past year, and young black men are more likely than young white men to have undergone the test, a new analysis shows.

The findings are published in the Sept. 15 issue of Cancer.

"That is a pretty amazing statistic, but not so hard to understand given the intense marketing of PSA testing for so many years," responded Dr. Steven Woloshin of Dartmouth Medical School and the VA Outcomes Group in an e-mail.

Woloshin reminds readers that we just don't know if screening does more good than harm.

He writes, "One thing that is often missing in the PSA discussion is the level of risk men face. This is of course crucial information: how else can you weigh the potential benefits and known harms if you don't know your chances to begin with? Unfortunately, the risk information isn't usually part of the discussion, or when it is it's usually given in aggregate terms. For example, you will read that 220,000 men were diagnosed last year or 28,000 died. Those numbers hide the fact that the risk changes dramatically with age; the numbers also do not provide context (ie, competing risks of death) for interpreting the risk."

To give people that context, Woloshin and colleagues Lisa Schwartz and Gilbert Welch recently published a paper in the Journal of the National Cancer Institute (JNCI). He explains, "The paper shows how we developed risk charts which present the 10-year chance of death from various causes (and all causes combined) at different ages. With regards to prostate cancer the charts show that for younger men there isn't a lot of risk to reduce with screening: out of 1000 men, less than 1 will die of prostate cancer in the next 10 years. Another way of saying that is more than 999 will NOT die of prostate cancer during this time."

You can see the risk charts yourself in the JNCI article.

Men are often told that this is just a simple blood test. Nothing could be further from the truth.

Over-reacting to the wrong risks

Two interesting columns are published today, each addressing some of the problems with current risk communication, and with public perception of risk.

The Washington Post has another excellent piece by the Dartmouth team of Woloshin-Schwartz-Welch, this one on how the flu death risk is often exaggerated, and so is the possible benefit of the flu vaccine.

The New York Times offers physician Abigail Zuger's essay, "Scare Yourself Silly, but the Real Terrors Are at Your Feet." She writes: "Of four patients I saw in a single hour last week, three announced how scared they were of the avian flu. I reassured them, but there was quite a bit I did not say, and here it is.

I did not say: If you want to be scared, then how about that drug habit of yours you think I don't know about? How about the fact that you are 100 pounds overweight and eat nothing but junk? How about the fact that in a few short months Medicaid is going to stop paying for your very expensive medications and no one knows how just high that Medicare Part D deductible and co-payment are going to be? I did not say: If you want something to be scared of, how about the drug-resistant Klebsiella that is all over this very hospital, an ordinary run-of-the-mill bacterial strain that has become so resistant to so many antibiotics that we've had to resurrect a few we stopped using 30 years ago because they were so toxic. ... Apparently they all lack the drama, the suspense, the titillating worst-case situations that energize our politicians and turn into a really newsworthy health care scare."

About this Archive

This page is an archive of recent entries in the Risk communication category.

Quality of care is the previous category.

Screening is the next category.

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