Investigators at a large academic medical center are analyzing data from a recent clinical trial investigating 'Medication Q', an experimental anticoagulant, for the prevention of recurrent deep vein thrombosis (DVT).
The trial included high-risk outpatients who were randomly and equally allocated to receive either Medication Q or a placebo. The results after months of follow-up are summarized below:
| Outcome | Medication Q Group () | Placebo Group () |
|---|---|---|
| Recurrent DVT | ||
| Major Bleeding Event |
Based on the trial data, which of the following statements regarding the statistical impact and clinical interpretation of Medication Q is most accurate?
- Treating 10 patients with Medication Q rather than placebo will prevent one recurrent deep vein thrombosis, whereas treating 25 patients will cause one additional major bleeding event.Answer
- BThe negative predictive value of Medication Q for preventing deep vein thrombosis will remain constant even if the medication is utilized in clinical settings with a higher baseline prevalence of the disease.
- CThe observed discrepancy in major bleeding events between the two groups implies that the medication's adverse effect profile is subject to confounding rather than effect modification.
- DA paired Student's t-test should be employed to calculate the statistical significance of the absolute risk reduction since the treatment and placebo arms represent matched continuous variables.
- EGiven the substantial relative risk reduction of approximately 77%, Medication Q should be empirically prescribed to all patients with a history of deep vein thrombosis, regardless of absolute pharmacological contraindications.
Answer
Treating 10 patients with Medication Q rather than placebo will prevent one recurrent deep vein thrombosis, whereas treating 25 patients will cause one additional major bleeding event.
The correct interpretation involves extracting the absolute risk data for both efficacy and safety. The Absolute Risk Reduction (ARR) for DVT is the control risk () minus the treatment risk (), which equals (). The Number Needed to Treat (NNT) is , yielding . This means patients must be treated to prevent one DVT. The Absolute Risk Increase (ARI) for major bleeding is the treatment risk () minus the control risk (), equating to (). The Number Needed to Harm (NNH) is , yielding . Therefore, treating patients causes one excess major bleeding event.
Step-by-Step Solution
Key Concept
The Number Needed to Treat (NNT) and Number Needed to Harm (NNH) are derived from the reciprocal of the absolute risk differences between treatment and control groups.
Estimated Time:1m 30s