A physician is reviewing a pharmaceutical advertisement for a newly approved oral anticoagulant indicated for the prevention of ischemic stroke in patients with non-valvular atrial fibrillation. The advertisement prominently features the headline: "Reduces the risk of ischemic stroke by 25% compared to standard therapy!"
The physician reviews the prescribing information provided in the fine print. According to the data from the pivotal 2-year clinical trial, the incidence of ischemic stroke in the control group receiving standard therapy was 8.0%.
Based on the provided data, what is the number needed to treat (NNT) with the new anticoagulant to prevent one additional ischemic stroke over a 2-year period?
Answer: 50 patients
Answer
50 patients
The number needed to treat (NNT) is the inverse of the absolute risk reduction (ARR). When a drug advertisement provides the relative risk reduction (RRR) and the baseline risk (Control Event Rate, or CER), the ARR must first be derived. The ARR is calculated by multiplying the CER by the RRR (). The NNT is then calculated as 1 / ARR (). Therefore, 50 patients need to be treated with the new anticoagulant for 2 years to prevent one additional ischemic stroke.
Step-by-Step Solution
Key Concept
Calculating Number Needed to Treat (NNT) from Relative Risk Reduction (RRR) and baseline risk.
Estimated Time:1m 0s