In a clinical trial involving a statin, what is the number-needed-to-treat (NNT) to prevent one cardiovascular event?

The number-needed-to-treat (NNT) is a crucial measure in clinical trials that indicates how many patients need to be treated with a particular intervention for one to benefit from it, preventing a specific outcome—in this case, a cardiovascular event.

To determine the NNT, the formula used is the inverse of the absolute risk reduction (ARR). ARR can be calculated by taking the difference in event rates between the treatment group and the control group. In this scenario, if the data indicates that for 1000 people treated with the statin, 50 will have a cardiovascular event as opposed to the 100 who would have had the event without treatment, the ARR would be 5% (100-50=50 events avoided out of 1000 treated).

Consequently, the NNT can be calculated as follows: NNT = 1/ARR. If we plug in our ARR of 0.05 (5%), we get NNT = 1/0.05, which equals 20.

This indicates that 20 patients must be treated with the statin to prevent one additional cardiovascular event. Understanding this measure can help healthcare providers weigh the benefits of statin therapy against potential risks and guide treatment decisions in clinical