Thursday, October 16, 2014

What is NNT?

It stands for the number needed to treat. It was developed in the 1980s by a trio of epidemiologists to weigh the benefits of a specific treatment. It describes how many people would need to take a drug for one person to benefit.

For example, it would take 2000 people to have a daily baby aspirin for one (nonfatal) heart attack to be prevented. The NNT here is 2000. Is it worth taking the aspirin? The doctors behind the NNT have a web site, TheNNT.com, that can be accessed to start answering the question. There is even a color-coding system to help you: Green for when a treatment makes sense, yellow for when more study is needed, red for when the harms and the benefits cancel each other out, and black when the harms outweigh the benefits.

The evangelists for NNT want doctors to base their treatments on good scientific evidence, not tradition, hunch, and the fear that patients will see them as doing nothing. The NNT can tell doctors when to do something and when something is not likely to be useful—or can even be harmful. "Once we, patients and families and doctors alike, get our heads around the idea that we shouldn’t always expect a drug or a procedure, we can begin to expect the right level of medicine and not just medicine for medicine’s sake."

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