Another number you will see is the Number Needed to Treat (NNT). This is the number of people that need to be treated with the drug under study in order to prevent one bad outcome. It is the inverse of the Absolute Risk Reduction. If the ARR is 1%, then the NNT is 100. That means that out of 100 people taking the drug, one of them will see a benefit. The other 99 will suffer the side effects (if any) for nothing.
Business Week did an article on statins that talks about the NNT for statin therapy. For people without heart disease but who have risk factors such as high blood pressure, the NNT to prevent one heart attack or stroke is 70-250 over 5 years. That’s a lot of people that think they are doing something to prevent a heart attack by taking the statin that are going to be really pissed when the chest pains hit.
When study results for a new (or old) drug are summerized, they can be shown several different ways.
- Absolute Risk Reduction (ARR), the difference between the event rate in the intervention group and the control group.
- Relative Risk Reduction (RRR), the AAR divided by the event rate in the control group.
Consider a trail for a new drug to treat heart attacks. 2000 people at high risk for a heart attack are tracked over a period of 10 years. They are split into two groups, one group gets the new drug (treatment group) and the other group doesn’t (the control group). After 10 years, 900 of the control group die due to a heart attack compared with 600 of the treatment group. The Relative Risk Reduction for the new drug is (90% – 60%) / 90% or 33%.
The Absolute Risk Reduction is just the difference in the two rates, 90% – 60% or 30%. Both of these numbers are about the same. Things change when we start talking about a low risk group.
Lets consider this same drug tested against a group of low risk individuals in the same manner. 2000 low risk patients are split into two groups and tracked over 10 years. At the end of the trial, 30 of the control group have died due to a heart attack or 3% and 20 of the treatment group or 2%. The Relative Risk Reduction is (3% – 2%) / 3% or 33%. Taking the new drug over 10 years will reduce your chance of a heart attack by 33%! Seems like a damn good idea.
The Absolute Risk Reduction is the difference between the two groups, or 1%. The new drug will save 1% over 10 years of low risk individuals. Not really worth it, especially if there are side effects.
Relative Risk Reduction does not take into account the initial baseline risk of the outcome event making a trivial improvement in mortality risk seem significant.
Interestingly enough, all of the studies I have seen summarized so far for cholesterol lowering drugs are only reporting relative risk reduction. More on this later.
Results of my last CT-Scan are back and the Superior Mesenteric Artery no longer shows inflammation. So now it’s all about not having a relapse. I will be tapering off of Prednosone starting with this week at 15mg and then dropping 2.5mg each week until I am off completely.
To completely clear my system and prevent relapse, Dr Pachaidee is putting me on Imuran. She wants me to start at 25mg for a week, then go to 25mg in the morning / 25 mg in the evening, ending up at 50mg in the morning and 50mg in the evening and stay on that dosage for a year. Which seems like a really fricking long time.
Imuran is an immunisuppresant that is primarily used in kidney transplants and for treatment of Rheumatory Arthritis. It is getting a lot of off label use in the treatment of inflammatory disorders such as Chron’s disease, Lupus and Vasculitis. I’ll be getting a complete blood count test and liver function test about two weeks into the imuran to make sure that I’m not one of the 1% that have a serious problem with the drug. If that test turns out okay, I’ll get tested on some less frequent schedule.
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I’ve had on and off again problems with a rash on my underarms from deodorant. I can’t use antiperspirant and I was switching brands trying to find one that wouldn’t irritate my underarms and having problems because just about all you can find in the store now is antiperspirant and very few that are just deodorant. I happened across a link to these deodorant stones googling around one day. Amazon lists some of them and the user comments said that they actually worked.
I was skeptical, but decided to give them a try as the other deodorants were really irritating my underarms. To my suprize, the stone actually works. I put a little bit of water on it and rub it all over my pits in the morning and it does the job. I have gotten up on Saturday and mowed the yard / crawled around the 150 degree attack all prior to showering and re-stoning. Covered in sweat but no bad odor at all, with conventional deodorant I would have been a stinky sweaty mess. With the stone, I was just a sweaty mess.
The salts in the stone kill the bacteria that live in your underarm and cause the odor. It will do nothing for your sweaty pits if you are used to using antiperspirant though.
