A primary care clinic is conducting a journal club on a newly published, randomized, double-blind, placebo-controlled trial. The trial evaluates a novel antiplatelet medication, 'Thrombo-Block', for the prevention of secondary ischemic stroke following a transient ischemic attack (TIA).
The study's promotional materials heavily emphasize a relative risk reduction of () for ischemic stroke.
A detailed review of the manuscript reveals the following:
- The absolute incidence of ischemic stroke over years was in the placebo group and in the Thrombo-Block group.
- A subgroup analysis stratified patients by the presence of chronic kidney disease (CKD).
- In the CKD subgroup, the relative risk (RR) for stroke with Thrombo-Block versus placebo was ( CI: ).
- In the non-CKD subgroup, the RR was ( CI: ).
Following the presentation, the clinical team discusses a -year-old male patient with a recent TIA, baseline CKD (stage ), and a history of severe recurrent gastrointestinal hemorrhage.
Which of the following statements regarding the study results and their application is most accurate?
- AThe stratified analysis indicates that chronic kidney disease acts as a confounding variable rather than an effect modifier in this trial.
- BThe patient should be initiated on the medication immediately, as the overall relative risk reduction heavily outweighs any risks associated with his history of gastrointestinal hemorrhage.
- The number needed to treat to prevent one ischemic stroke over years in the overall study population is .Answer
- DIf a new screening test for stroke risk is applied to the population taking the medication, the positive predictive value of the test will remain unchanged compared to the placebo group.
- EThe attending physician's quick rejection of the drug due to a vivid memory of a single patient having a severe bleed on a similar drug last week is an example of anchoring bias.