In a review of a new book, Doctored by Sandeep Jauhar, Dr. Thomas P Stossel (identified as the American Cancer Society Professor of Medicine at Harvard Medical School) gives us a misleading statistic presented as medical information. Read the article here.

Dr. Stossel writes, “Death due to cardiovascular disease, Dr. Jauhar’s specialty, is 60% lower today compared to that era, predominantly thanks to the ability of physicians to apply clinically effective technologies—overuse of them notwithstanding—that save, prolong and improve lives.”

Now, when you see a number like “60% lower” (or 60% higher), your medical information red flags should kick in. That number is relative. It could mean that deaths went down from 100 out of ten million to 40 out of ten million.

Sure enough, the numbers here aren’t that different. Just google “death rates from heart disease down by 40%.” When I did, I got many hits, sharing the same information. As reported by this article in The Baltimore Sun:

In 1950, the death rate from heart disease was 307.4 per 100,000 people. In 1996, it was 134.6. In 1950, the stroke death rate was 88.8 per 100,000 people. In 1996, it was 26.5.

So in 46 years the death rate from heart disease was reduced by about 173 per 100,000. That’s a little less impressive than 60%.

But thinking mathematically isn’t just about computing numbers. The number 173 might include changes in the way deaths were coded, contributing to inaccuracy of medical information. In other words, back in 1950, some medical examiners might have attributed deaths to heart attacks but today will record them more accurately as something else. Researchers are aware of distortions in reporting causes of death; for example, see this article.

But let’s suppose that deaths were indeed reduced by 173 per 100,000. What is the quality of life for those whose lives were spared? Are they cardiac cripples, languishing in nursing homes? Or have they been returned to meaningful opportunities for work and play? Lacking this data, the medical information is distorted.

We must continue to be skeptical when reading any news reports of medical information, especially when headlines seem to proclaim very good or very bad news.