Microsoft word - number needed to treat/nnt.doc

Medicine's Dirty Little Secret Wikipedia, the free encyclopedia; Time Magazine; Dr. Joseph Mercola
There's one medical statistic doctors don't much talk about despite its importance. It's called the
NUMBER NEEDED TO TREAT, or NNT and it’s one of the best-kept statistical secrets in medicine.
When the NNT statistic was first developed in 1988, it was intended to help you make a decision aboutwhether or not to take a drug. Having it put in simple terms such as “Out of every 50 people who take thisdrug, perhaps one heart attack will be prevented, and the other 49 people will receive no benefit,” putsthings into perspective … a perspective that the drug companies do not want you to see.
One example of how drug companies have hidden NNT lies with cholesterol drugs. These drugs, which cancause side effects like liver damage, muscle weakness, cognitive impairment and many, many others, aretouted as miracle pills that can slash your risk of a heart attack by more than one-third.
BusinessWeek did a story on this topic and found the REAL numbers right on Pfizer’s newspaper ad forthe cholesterol-lowering drug Lipitor. Upon first glance, the ad boasts that Lipitor reduces heart attacks by36 percent. But there is an asterisk. Much smaller type states: "In a large clinical study, 3% of patientstaking a sugar pill or placebo had a heart attack compared to 2% of patients taking Lipitor." What thismeans is that for every 100 people who took the drug over 3.3 years, three people on placebos, and twopeople on Lipitor, had heart attacks. Taking Lipitor resulted in just one fewer heart attack per 100 people.
The NNT, in this case, is 100. 100 people have to take Lipitor for more than three years to prevent oneheart attack. And the other 99 people have dished out hundreds of dollars and increased their risk of alaundry list of side effects. Not to mention that this study was funded by the industry, which means theirresults may already be skewed, and the actual benefit may be even LESS than what they found.
Many Drugs are “Worse Than a Lottery Ticket”
According to Dr. Nortin M. Hadler, professor of medicine at the University of North Carolina at ChapelHill, in Business Week: "Anything over an NNT of 50 is worse than a lottery ticket; there may be nowinners." The NNT for some cholesterol-lowering drugs has been figured at 250 and up, even after takingthem for five years. "What if you put 250 people in a room and told them they would each pay $1,000 ayear for a drug they would have to take every day, that many would get diarrhea and muscle pain, and that249 would have no benefit? How many would take it?" Dr. Jerome R. Hoffman, professor of clinicalmedicine at the University of California at Los Angeles, asked Business Week. The answer, of course, isfew to none. And that is exactly why you have probably never heard of NNT.
The Moral of the Story: Ask your doctor questions.
You wouldn’t simply buy a car without finding out the real bottom line so don’t blindly accept the numbersthat doctors and the drug companies tell you. Ask your doctor or pharmacist to tell you the NNT for anyprescription you’re considering. Only take medication as an absolute last option. Diet, exercise and lifestylemodifications may work just as well.
From Wikipedia: The number needed to treat (NNT) is an epidemiological measure used in
assessing the effectiveness of a health-care intervention, typically a treatment with medication. The
NNT is the number of patients who need to be treated in order to prevent one additional bad outcome
(i.e. to reduce the expected number of cases of a defined endpoint by one). It is defined as the inverse
of the absolute risk reduction. It was described in 1988.
Relevance
The NNT is an important measure in pharmacoeconomics. If a clinical endpoint is devastating enough
(e.g. death, heart attack), drugs with a high NNT may still be indicated in particular situations. If the
endpoint is minor, health insurers may decline to reimburse drugs with a high NNT.

Source: http://loryngalardi.com/articles/medicine.pdf