Subtle variation on gaining weight to become taller

Back in March I wrote a blog post asking whether gaining weight makes you taller. Weight and height are clearly associated, and from that data alone one might speculate that gaining weight could make you taller. Of course causation is in the other direction: becoming taller generally makes you gain weight.

In the 1980’s, cardiologists discovered that patients with irregular heart beats for the first 12 days following a heart attack were much more likely to die. Antiarrythmic drugs became standard therapy. But in the next decade cardiologist discovered this was a bad idea. According to Philip Devereaux, “The trial didn’t just show that the drugs weren’t saving lives, it showed they were actually killing people.”

David Freedman relates the story above in his book Wrong. Freedman says

In fact, notes Devereaux, the drugs killed more Americans than the Vietnam War did—roughly an average of forty thousand a year died from the drugs in the United States alone.

Cardiologists had good reason to suspect that antiarrythmic drugs would save lives. In retrospect, it may be that heart-attack patients with poor prognosis have arrhythmia rather than arrhythmia causing poor prognosis. Or it may be that the association is more complicated than either explanation.

Related: Adaptive clinical trial design


8 thoughts on “Subtle variation on gaining weight to become taller

  1. I’m not a public health expert, but I imagine some of these improvements were discovered and promulgated without expensive trials. Make some change that you know can’t do any harm — say making some sanitation standard more demanding — and then see what happens. “Hey, that made a bigger improvement than we expected. Let’s tell our colleagues.”

    Have you seen The Checklist Manifesto? Sometimes a simple checklist makes a huge difference.

  2. Hi, I’m impressed with the amount of books that you cite. Do you read them all in our free time?

  3. The amount of damage that confusions in medicine can cause is tragic. This example really makes me wonder whether the default assumption should be to take no action until correlational results are replaced by randomized experiments in medicine. It’s hard to assess from single examples whether the tendency to jump on the bandwagon with new treatments is more harmful or helpful to the world. Examples like the horrors of the frontal lobotomy come easily to mind, but, of course, that sort of reasoning is highly susceptible to both the availability bias and prospect theoretic overweighting of negative events.

  4. Randomized trials aren’t perfect either. Freedman spends several pages going over ways that randomized trials can go wrong. And besides, there has yet to be a randomized trial showing that parachutes save lives.

  5. That paper is wonderful: I remember discovering during my first year and thinking that it was a far more compelling example than Cohen’s famous line about the Earth being round.

    Given the difficulties with randomized trials, what are we to do? Plainly, medicine has improved our health since the start of the 20th century, and so it seems to me that we have to continue experimenting. Is the best we can hope for that our mistakes are not in vain?

  6. Most of the improvement in health in the 20th century was due to better sanitation, improved hospital procedures, etc. Mundane things that don’t make headlines. Not blockbuster drugs etc.

  7. And it’s not as if doing nothing is always harmless–do we need to wait for randomized trials to demonstrated the effectiveness of the Heimlich maneuver?

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