Risk

Summary

In this episode of Sketch EBM, host Anthony Croco explores the complex concepts of risk in medical research, particularly focusing on absolute risk reduction (ARR), relative risk (RR), and relative risk reduction (RRR). He explains these terms using fictional study examples, illustrating how misleading interpretations of these statistics can impact perceptions of treatment benefits. Croco emphasizes the importance of understanding absolute risk reduction as a more accurate measure of risk and encourages skepticism towards reports that only highlight relative risk reduction. Ultimately, viewers are urged to critically evaluate the data presented in research and marketing.

Takeaways

• 📊 Risk is often discussed in terms of harm versus benefit, rather than just risk versus benefit.
• ⚖️ It's essential to consider both the probability of harm and the probability of benefit when discussing risk.
• 🔍 Common concepts in risk analysis include absolute risk reduction (ARR), relative risk (RR), and relative risk reduction (RRR).
• 📉 Absolute risk reduction (ARR) is calculated by subtracting the experimental event rate from the control event rate.
• 📈 Relative risk (RR) is determined by dividing the experimental event rate by the control event rate.
• 📉 Relative risk reduction (RRR) measures the proportion of affected individuals in the control group who would benefit from the experimental intervention.
• ⚠️ The absolute risk reduction can sometimes present a significantly different perspective compared to relative risk reduction.
• 🧪 In a hypothetical study, while the relative risk reduction may indicate a 33% benefit, the absolute risk reduction could be as low as 1%.
• 💡 It’s crucial to be skeptical when only relative risk reduction is reported, as it can be misleading.
• 📖 Understanding these concepts allows for more informed decisions in evaluating interventions and therapies.

Q & A

What is the main topic discussed in the video?

The main topic is risk, particularly the concepts of absolute risk reduction, relative risk, and relative risk reduction.

How is risk commonly framed in discussions?

Risk is often framed in terms of harm versus benefit, emphasizing the potential negative outcomes of an action or decision.

What do the acronyms ARR, RR, and RRR stand for?

ARR stands for Absolute Risk Reduction, RR stands for Relative Risk, and RRR stands for Relative Risk Reduction.

What is absolute risk reduction (ARR) and how is it calculated?

Absolute risk reduction (ARR) is the difference between the control event rate and the experimental event rate. It shows the actual percentage of participants who benefit from an intervention.

How is relative risk (RR) calculated?

Relative risk (RR) is calculated by dividing the experimental event rate by the control event rate, providing a ratio that indicates how much the risk changes between groups.

What does relative risk reduction (RRR) indicate?

Relative risk reduction (RRR) indicates the proportion of affected individuals in the control group who would benefit from the experimental intervention, calculated as the difference in risk between the two groups relative to the control group.

Can you provide an example of how these risks are applied in a study context?

In a fictional study with a control group and an experimental group, if the control event rate is 60% and the experimental event rate is 40%, the ARR would be 20%, the RR would be 67%, and the RRR would be 33%.

Why is it important to distinguish between absolute and relative risk reduction?

It's important because relative risk reduction can present a misleading picture of the benefits of an intervention, as seen in the example where a 33% reduction was mentioned, but the actual benefit was only 1% (ARR).

What caution should be taken when interpreting risk reduction statistics?

One should be skeptical if only relative risk reduction is reported, as it may exaggerate the effectiveness of a treatment compared to absolute risk reduction.

What final takeaways does the host suggest regarding understanding risk?

The host emphasizes remembering that risk is associated with harm, using absolute risk reduction for a clearer picture of benefits, and being cautious about the interpretation of relative risk reduction.