What do we know about communicating risk? A brief review and suggestion for contextualising serious, but rare, risk, and the example of cox-2 selective and non-selective NSAIDs.

R Andrew Moore,Sheena Derry,John Paling,Henry J Mcquay

doi:10.1186/ar2373

Abstract

BackgroundCommunicating risk is difficult. Although different methods have been proposed – using numbers, words, pictures or combinations – none has been extensively tested. We used electronic and bibliographic searches to review evidence concerning risk perception and presentation. People tend to underestimate common risk and overestimate rare risk; they respond to risks primarily on the basis of emotion rather than facts, seem to be risk averse when faced with medical interventions, and want information on even the rarest of adverse events.MethodsWe identified observational studies (primarily in the form of meta-analyses) with information on individual non-steroidal anti-inflammatory drug (NSAID) or selective cyclooxygenase-2 inhibitor (coxib) use and relative risk of gastrointestinal bleed or cardiovascular event, the background rate of events in the absence of NSAID or coxib, and the likelihood of death from an event. Using this information we present the outcome of additional risk of death from gastrointestinal bleed and cardiovascular event for individual NSAIDs and coxibs alongside information about death from other causes in a series of perspective scales.ResultsThe literature on communicating risk to patients is limited. There are problems with literacy, numeracy and the human tendency to overestimate rare risk and underestimate common risk. There is inconsistency in how people translate between numbers and words. We present a method of communicating information about serious risks using the common outcome of death, using pictures, numbers and words, and contextualising the information. The use of this method for gastrointestinal and cardiovascular harm with NSAIDs and coxibs shows differences between individual NSAIDs and coxibs.ConclusionAlthough contextualised risk information can be provided on two possible adverse events, many other possible adverse events with potential serious consequences were omitted. Patients and professionals want much information about risks of medical interventions but we do not know how best to meet expectations. The impact of contextualised information remains to be tested.

Highlights

Many factors contribute to an incomplete understanding and evidence base for risk and risk presentation
People tend to underestimate common risk and overestimate rare risk; they respond to risks primarily on the basis of emotion rather than facts, seem to be risk averse when faced with medical interventions, and want information on even the rarest of adverse events
Conclusion contextualised risk information can be provided on two possible adverse events, many other possible adverse events with potential serious consequences were omitted

Summary

Introduction

Many factors contribute to an incomplete understanding and evidence base for risk and risk presentation. Decisions are based on facts and emotions, both of which may be manipulated, and it may well be that emotions dominate the facts This is important in the framework of medical decision-making and in the choice of pharmacological and interventional therapies for individuals. NSAID or coxib The main patient-specific influences on the background incidence of both gastrointestinal bleeding and myocardial infarction are age and sex. As regards non-users of NSAIDs, Mamdani and colleagues [74] reported a rate of myocardial infarction of 8.2 per 1,000 person years. We used background rates of 2.2 per 1,000 for gastrointestinal bleed and 8.2 per 1,000 for myocardial infarction as being typical of non-users of NSAIDs or coxibs selected as controls in large observational studies This is in line with reports of the incidence of acute myocardial infarction without including pre-admission deaths from Holland [75] and England [76].

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