Tuesday, November 11, 2008

Medical Study Rant

Yesterday, newspapers headlined the New England Journal of Medicine study that showed that if healthy people took statins (like Crestor) to reduce their otherwise normal levels of cholesterol, their chances of having a cardiac event would be reduced by 44%. Good news, right?! Just take a $3 pill a day for the rest of your life, and you won't have a heart attack or stroke. This is one of those stories from the pharmeceutical/medical/industrial establishment that drives me crazy.

So, let's dig a little bit to find the deeper truth. Well, not much deeper. None of the facts reported were false, but the fanfare is way out of proportion with the actual results. There were 17,802 people in the study, divided into two groups of 8,901. One group took Crestor (big surprise - the study was financed by AstraZeneca, the makers of Crestor); the other took a placebo. The study was ended early because the results were so good. Here are the final results:
  • Cardiac events: Control group-251, Crestor group-142. Risk reduction-43%
  • Cardiac deaths: Control group-157, Crestor group-83. Risk reduction-47%
  • Deaths from all causes: Control group-247, Crestor group-198. Risk reduction-20%

This all sounds great, right? But put it in perspective. 251 cardiac events in a group of 8,901 is 2.8%. So if you fit the profile of the group tested (men over 50, women over 60, all in otherwise good health with no history of heart disease), you have a 2.8% chance of a cardiac event over the 1.9 years of the study. By any measure, that is a pretty small risk. Taking Crestor, at a cost of $100/month, lowers that already low risk by 43% to 1.6%. Another way of looking at it is that you've decreased your risk by 1.2 percentage points. Somehow that doesn't sound as good as 44%, does it? 44% might be worth $100/month, but are 1.2 percentage points?

Another way of looking at the manipulation of these statistics is that with no drugs, your chances of dying from something other than heart disease is 1.0% ((247-157)/8901 x 100). With Crestor, your chances are 1.3%((198-83)/8901 x 100).

So - your chances of dying of something other than heart disease is 30% greater if you take Crestor than if you take nothing. How would that headline sound? It would be perfectly true!

1 comment:

NatalieLaughing said...

Wow... I know you can manipulate statistics... but holy cow... My first thought was.. maybe we should all take that drug.., because the stats look so good.. but then upon your analysis... it make it more clear. I am leary of any statistics. So many people take drugs they think they can't live without...
Natalie