Morning Report Unknown

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Morning Report Unknown

• 3/27/06

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Problem

• A placebo-controlled trial of a medication
  involved 100 patients 50 received study
  medication and 50 received placebo.
• Ten patients receiving the study drug died during
  the trial, and twenty patients died who were
  receiving placebo.
• What is the number needed to treat to prevent one
  death using this medication?

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(No Transcript)
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Answer

• Mortality Rates

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• Calculate absolute risk reduction or risk
  difference
• 40 - 20 20
• NNT 1/20 1/.2 5

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NNT

• The NNT is a popular expression of absolute
  benefit or risk.
• A few caveats about the NNT
• NNTs from different studies cannot be compared
  unless the methods used in the studies are
  identical.
• Calculation of the NNT depends upon the control
  rate (ie, the rate of events in the control arm).
  The control rate can be variable (particularly in
  small controlled trials, which are more
  vulnerable to random effects).