Final answer:
Approximately 10 patients need to be treated for one to benefit from the new preventative medication, based on the absolute risk reduction calculated using the intention to treat approach.
Step-by-step explanation:
Using an intention to treat approach, to calculate how many patients need to be treated before a benefit is seen, we use the concept of Number Needed to Treat (NNT).
The NNT can be calculated from the results of the study: out of 224 patients in each group, 45 patients developed the disease with the new medication, and 68 developed the disease in the control group without the medication.
To find the NNT, first, we determine the absolute risk reduction (ARR) which is the difference in the event rates between control and treatment groups: ARR = (68/224) - (45/224) = 0.1027. Then, NNT is the inverse of ARR: NNT = 1 / ARR.
So the number of patients that need to be treated for one to benefit is NNT = 1 / 0.1027, which approximately equals 9.74. Therefore, approximately 10 patients need to be treated for one patient to benefit from the new preventative medication.
This example demonstrates the importance of NNT in evaluating the effectiveness of a treatment. It also exemplifies why such calculations are critical in making informed decisions in healthcare and pharmaceutical research, balancing the desire for effective treatment with considerations for cost, side effects, and benefit maximization.