At first I wasn't going to recommend this book, because I thought it was too simple. But I'm finding myself using the ideas they develop every time I read an article about health, and they are useful.They point out that benefits of drugs are often talked about in terms of relative improvement: "Drug X reduces your risk of heart attack by 20%." But without knowing your absolute risk of having a heart attack, you can't tell if this is important or not. If your risk of having a heart attack is 1%, and the drug reduces it to 0.8%, this is obviously a different matter than if your risk is 50%, and the drug reduces it to 40%. And even the better case, do you care about at reduction from 50% to 40%? What are the side effects like?
I'm extrapolating a bit here, but I think the authors would like to see the FDA require drug companies to put a standard chart in ads and product literature that lists the effectiveness (and side effect percentages) of placebo and drug treatment. This would be a standard drug information label like the standard nutrition labels we have on all our foods. I was certainly startled to see how small the effects of many interventions are.
For instance, folic acid supplementation is recommended for all women of child-bearing age. The March of Dimes has run ads comparing not taking folic acid to letting your baby crawl out into traffic. And yet without folic acid supplements, you have a 2/1000 risk of neural tube defects, and with folic acid a 1/1000 risk. So it's worth taking folic acid because the cost and side effects are negligible, but it is making a very small risk even smaller.
The authors also cover risks and benefits of mammograms and PSA testing, which are now being better discussed by the media. I'd think very hard before having either one.
A deceptively easy read, because the ideas are so important and relevant.
Know Your Chances: Understanding Health Statistics
Steve Woloshin, Lisa M. Schwartz, H. Gilbert Welch
2008
Available from Amazon
No comments:
Post a Comment