Number Needed to Treat (NNT) and Number Need to Harm (NNH)

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Written By: 
Nicole Slater, PharmD Candidate

This informative tutorial describes two easy to calculate statistical tools - NNT and NNH - that help you analyze the results of clinical trials in a clinically meaningful way and help you make decisions based on benefit vs. risk.  The example given - the benefits and harms of clotostrapzin - is fictitious and merely intended to illustrate the concepts discussed.

 

 



Comments

1

I like how you presented the concept of NNT! I really like the graphics. One small suggestion -- the definition of NNT is the number of patients needed to be treated to prevent or cause one ADDITIONAL outcome (http://www.cebm.net/number-needed-to-treat-nnt/), since it compares event rates. The EER tells the number of people that need to be treated to prevent or cause one outcome. Another suggestion -- when calculating NNT or NNTH, rather than requiring users to convert the percentage into an absolute value, have people divide the ARR (as a percent) into 100. For example, your ARR is 16% -- dividing 16 into 100 can be done mentally and is easier than 1/0.16. Nice job! Allen