Deliberately Misleading Drug Studies: Is it a Medical Shell Game?

To appreciate how easily people and most physicians can be fooled, consider this: Which drug would you rather take, one that reduces your risk of cancer by 50 percent, or another drug that only reduces your risk of cancer from two to one out of 100? Most people would choose the drug that reduces their risk of cancer by 50 percent, but in fact both these numbers refer to the same outcome. They’re just two different ways of looking at the same numbers. Without any qualification, both statements “reduced the risk by 50%” and “reduced the risk by 1 in a hundred” (1%) are examples of absolute or relative difference. But note the difference in “feel” between 50% and 1%. Which figure sticks in your mind?

So the use of one definition “relative risk” in particular is both misleading and dangerous, especially when drug promotion is involved. Most clinical researchers using data to compare two or more different groups, almost always present their results in confusing ways to emphasize a point of view. An absolute difference is a subtraction; a relative difference is a ratio, but they’re just two ways of propagating confusion by expressing a result by using two different sets of numbers. Of course, they don’t always supply all the numbers, especially the Absolute differences.

For example, the headlines read, “Tamoxifen Cuts Breast Cancer Risk by 33% in Healthy Women!,” yet it turns out, among all the women in a study who took Tamoxifen, less than 2% got breast cancer, and among those that took the placebo, less than 3% got breast cancer. The real difference was 1%, in this series, of questionable significance.{“How to Lie With Statistics,” Real Health Breakthroughs, Dr. William Campbell Douglass, 2004}

Keep in mind that headlines promoting a drug will almost always refer to relative risk, “A breathtaking 40% reduction in risk!” -and this numerical shell game will be copied in the mainstream media, press, medical journals. Pharmaceutical companies, marketing reps, even some physicians anxious to publish and usually supported by commercial drug interests are constantly pushing and exaggerating the supposed benefits of their drugs while minimizing their risks. As the old saw goes: Figures don’t lie, but liars can sure figure.

More to come.

Martin F. Sturman, MD

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