What have you changed you mind about lately?

I wrote in my last blog entry that one of the great things about Evidence Based Medicine (EBM) is that when new evidence comes along you are duty bound to change your view. There is no embarrassment or regret, you simply acknowledge that the data have improved and your views have moved on. If you hold a view despite there being no credible evidence and later it turns out that you are correct you aren’t vindicated. You are actually someone who got it wrong but got lucky. 

If you lived in the Middle Ages and decided on a whim, with no evidence whatsoever that continents moved across the oceans people would have called you a fool. The fact that evidence of continental drift was produced later on doesn’t stop you being a fool, it just makes you a lucky one. You could say something similar about Low Carb High Fat (LCHF) diet followers. Currently there is very little evidence to support their views but it remains possible that in future we might learn that there are significant benefits from the diet. Were that to happen these people would not be vindicated, they would remain, in my view, a poor judge of evidence, just lucky ones.

This brings me to the point of my post which is that I recently changed my mind about something. I wrote in a piece called ‘we need to talk about statins’ http://www.amazon.com/We-need-talk-about-statins-ebook/dp/B00N3T3GQ0 that I didn’t think there was good evidence of a causal relationship between high LDL cholesterol and heart disease. I based this on the fact that many drugs had been used to lower LDL cholesterol but only one class, the statins, had also reduced heart disease. It seemed to me that if a causal relationship existed multiple ways of reducing LDL would work.

Three recent trials have been published which have forced me to change my view. In the IMPROVE-IT trial patients were given ezetimibe, which reduces gut absorption of cholesterol. In the OSLER and ODYSSEY LONG TERM trials patients were given a drug that inhibits an enzyme called PCSK9 which is an alternative way of reducing LDL. In all 3 trials there was a small be significant effect of the drugs on ‘hard’ outcomes like heart attacks. So now, instead of there being only 1 class of drugs that both lowers LDL and cardiovascular events there are 3 classes. This has led me to change my view and believe that a causal link probably does exist. There's no regret, at one point I didn't think there was enough evidence, and now I think there is. Until something new comes along of course.

References

 

Lowering LDL Cholesterol Is Good, but How and in Whom? Neil J. Stone, M.D., and Donald M. Lloyd-Jones, M.D. NEJM http://www.nejm.org/doi/ref/10.1056/NEJMe1502192#t=article#t=references

Proof That Lower Is Better — LDL Cholesterol and IMPROVE-IT John A. Jarcho, M.D., and John F. Keaney, Jr., M.D.

http://www.nejm.org/doi/full/10.1056/NEJMe1507041