Do patients better understand absolute numbers when discussing risks?

Communicating Risk to Patients: Absolute Numbers Enhance Understanding

Yes, patients better understand absolute numbers when discussing risks, and it's generally best to communicate risk in terms of absolute risk rather than relative risk, as individuals tend to be influenced by relative risk information. 1

Why Absolute Risk Is More Effective

Absolute risk provides patients with a clearer understanding of their actual situation for several key reasons:

• Provides clear reference class: Absolute numbers clarify the reference group. For example, saying "Of 10 patients on this medication, 3 to 5 will experience this side effect" makes the reference class clear, unlike saying "30-50% risk of side effects" 1

• Reduces misinterpretation: Relative risk presentations can lead to overestimation of effects, while absolute risk gives a better representation of the actual situation 2

• Improves decision-making: Studies involving breast cancer patients found that quoting absolute survival benefit is easier for patients to understand compared with relative risk reduction 1

Best Practices for Risk Communication

Use Multiple Formats

• Present risk information in multiple numerical formats to accommodate different preferences 1
• Use consistent denominators (preferably 10 or 100) when comparing risks 1
• Round to whole numbers when possible 1

Visual Aids Are Powerful

• Pictographs with 100 boxes are particularly effective for communicating percentages 1
• Bar charts work well for making comparisons, while line graphs are better for showing trends 1
• Visual aids improve understanding particularly for those with lower levels of education and numeracy 1

Framing Matters

• Present both positive and negative frames (e.g., "60% risk of developing a condition also means 40% risk of not developing it") 1
• Both physicians and patients are susceptible to framing bias 1
• Use consistent numeric formats to facilitate interpretation 1

Examples of Good vs. Bad Risk Communication

Good Examples:

1. Using absolute risk with clear reference: "Out of 100 patients with these risk factors, 60 will develop the condition and 40 will not" 1

2. Providing multiple formats: "There is a 25% chance of this side effect, or 25 in 100 patients will experience it" 1

3. Using visual aids: Showing a pictograph of 100 people with 25 shaded to represent those affected 1

4. Consistent denominators: "Treatment A reduces risk to 5 of 100 people compared to Treatment B which reduces risk to 15 of 100 people" 1

5. Both positive and negative framing: "This treatment reduces your risk of dying from this cancer from 50% to 40%. This means that without treatment, 50 out of 100 people would die, but with treatment, 40 out of 100 would die and 60 would survive." 1

Bad Examples:

1. Using relative risk alone: "This treatment reduces your risk by 20%" (without providing baseline risk) 1, 2

2. Using numbers needed to treat (NNT): Studies show NNT is often misinterpreted by patients and should not be used alone 3

3. Inconsistent denominators: "1 in 50 compared with 1 in 1,000" (makes comparison difficult) 1

4. Using qualitative modifiers only: Terms like "high risk" or "low risk" allow greater latitude for interpretation than quantitative formats 1

5. Large denominators: Risk figures with denominators greater than 5,000 are often incorrectly recalled or disregarded 1

Common Pitfalls to Avoid

• Denominator neglect: Patients with low numeracy often focus only on numerators when comparing risks 1
• Emotional distortion: Factual risk information may take second place to "gut feelings" and personal experiences 1
• Overcomplication: Keep information simple and assume low numeracy 1
• Ignoring individual preferences: Some patients prefer general terms versus specific numbers or visual aids 1
• Using relative risk reduction alone: This can bias patients' perception of a therapy's effectiveness, making benefits appear more favorable 1

By presenting absolute risks clearly, using visual aids, and providing multiple formats, clinicians can significantly improve patients' understanding of risk information, leading to better informed decision-making about their health.