A physician is evaluating a promotional brochure for a novel cardioprotective agent, 'Cardio-X.' The advertisement's headline prominently asserts: "Reduces the risk of major adverse cardiovascular events (MACE) by 50%!"
Seeking to understand the true clinical impact before prescribing it to a patient, the physician reviews the primary 5-year randomized controlled trial data included in the fine print.
The trial included 5,000 patients randomized equally into a treatment group and a placebo group. The results table is as follows:
| Endpoint | Placebo (n = 2,500) | Cardio-X (n = 2,500) | p-value |
|---|---|---|---|
| Composite MACE | 300 (12.0%) | 150 (6.0%) | < 0.001 |
| Non-fatal Myocardial Infarction | 125 (5.0%) | 50 (2.0%) | 0.002 |
| Non-fatal Stroke | 50 (2.0%) | 25 (1.0%) | 0.03 |
| All-cause Mortality | 125 (5.0%) | 75 (3.0%) | 0.04 |
Based on the trial data provided, what is the number needed to treat (NNT) with Cardio-X to prevent one death from any cause over the 5-year period? (Enter the numerical value)
Cevap: 50 patients
Cevap
50
The number needed to treat (NNT) is calculated as the inverse of the absolute risk reduction (ARR), which is expressed as . First, the relevant endpoint must be identified from the advertisement's data table. Although the promotional material heavily emphasizes the relative risk reduction in the composite MACE endpoint, the clinical question specifically asks for the metric related to preventing all-cause mortality. According to the table, the absolute risk of all-cause mortality is () in the placebo group and () in the treatment group. The Absolute Risk Reduction (ARR) is . Therefore, the NNT is . This means patients would need to be treated with Cardio-X over years to prevent one death from any cause.
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Calculation of Number Needed to Treat (NNT) and interpretation of clinical endpoints vs. composite endpoints in medical literature.