Risk - Chances are...

TO BE HUMAN is to make judgements about risks and benefits on a regular basis. Shall I cross the road here? Should I accept the invitation to the party? Should I stay late at work and annoy my spouse – or go home on time and maybe annoy my boss? We are pretty good at all of this – using a series of automatic decision-making shortcuts known as heuristics (well described on Wikipedia).

But sometimes these short-cuts let us down. Making a decision about medical treatments can be such a time. A patient’s instincts can lead to poor judgements and it is the job of a doctor, dentist or other clinical professional to communicate risks and benefits in an effective manner.

Until very recently, communicating risk was not taught at medical, dental or nursing schools and yet there is useful evidence from a number of fields that can assist us in this task.

There are situations in which clinicians already routinely attempt to counsel risks and benefits. An obvious one would be seeking formal consent (for surgery or other interventionist procedures). The prescription of some drugs (e.g. warfarin) also falls into this category. However, on reflection it can be seen that any action, or indeed non-action, by a clinician is attended by risks and benefits that must be communicated to patients. Deciding whether or not to undergo surgery, to take a medication, to agree to screening, or pursue a diagnosis are examples of judgements where it may be possible to find data to assist clinical decision-making.

Increasingly, patients approach us with information gleaned from the internet – some of which may be inaccurate. Again, we need to be skilled in being able to help educate such a patient.

Below are some common challenges clinicians face in communicating risks to patients:

Innumeracy. Even those of us with decent maths qualifications find it hard to get our head around risk data, whether presented as frequencies (e.g. percentages), odds etc. Many of our patients will not have formal maths qualifications and few people routinely use maths in their daily lives.

Getting good data. There can be a shortage of good data and even where there is relevant evidence it is often inaccessible. This means that the clinician in the front line may not be able to give a precise answer to the questions, “How likely is this to help me?” and “How big are the risks?”

Knowing how to represent data. Experiments (in applied psychology and other fields) have shown that the brain’s wiring prevents instinctive understanding of standard formats for considering risk – the two commonest being frequencies (e.g. percentages) and odds ( e.g. “1 in 28 chance”).

So what are we to do? There is sufficient evidence to offer some guiding principles to clinicians:

• Pictures seem to be understood most easily. Numbers next. Words alone are in last place.
• Use natural frequencies. Express the data as a number in a larger number. For example: “Out of 100 people like you who take this drug, four would get one of these sideeffects in one year”.
• Frame positively as well as negatively. Following on the previous example: “This means that 96 people out of 100 would experience no side-effects in one year”.
• Give absolute risks before relative risks. For example: “If 100 people had the condition, 10 would die without treatment. If 100 people have the operation, only 5 would die. In other words, this operation halves your risk of dying”.
• Use graphs. For single or very simple conditions, a pictogram/crowd chart is preferred (1000 little men, or smiley faces, or similar). For presenting several facts at once (e.g. risks and benefits of HRT) then a bar chart is preferred.

There is no magic bullet for communicating about risk. This is a difficult task even with well-educated patients and good data. The above principles are based on best current evidence and there is clearly scope for us to do a better job for our patients.

Dr Malcolm Thomas is a GP and founder of the training company EPI

FURTHER READING

• http://en.wikipedia.org/wiki/Heuristic
• Gigerenzer G. Reckoning with risk. London: Penguin; 2005
• Communicating Risks. BMJ themed edition. 27 Sep 2003