The Risky Business of Medical Procedures

By Jane Farrell

How cautious are you in deciding on a medical treatment?

In exploring that question, a team of European researchers found that people underestimate the risks of treatments ranging from minor drugs to major and overestimate the benefits.

Published in the journal Risk Analysis, the study of 376 adults was led by Professor Yaniv Hanoch from the University of Plymouth School of Psychology, UK, together with Jonathan Rolison from the University of Essex, UK and Alexandra Freund from the University of Zurich, Switzerland.

In several hypothetical scenarios, the researchers asked participants to imagine that their doctor had recommended a treatment – a drug, dental surgery, ear surgery, kidney operation, or to take a newly developed medication – in order to treat an eye infection, a gum infection, a hole in their eardrum, a benign growth, and a blood disorder, respectively.

There’s a growing body of evidence regarding patients’ unrealistic optimism about medical treatment.

In each scenario, they were provided with precise information about the probability of success (saving a tooth) or the probability of the risks (liver damage). The treatments and side effects were taken from medical studies, but the probabilities of their happening were devised by the study authors for the research only.

Participants were then asked to indicate how likely they believed that they were to experience one of the benefits or risks by moving a pointer on a scale from 0% to 100%.

Results showed that on average, people perceived the benefit as higher than the benefit midpoint (average) actually was. In the case of the tooth, the perceived likelihood of benefit was 48%, compared with the midpoint of 45%. The perceived risk of the side effects – in the case of the dental procedure, a possible gum infection – was perceived to be 46%, compared to the risk average of 50%.

The biggest difference came with the most serious procedure: a kidney operation for a benign growth. The participants perceived a risk of 43 percent for paralysis, the worst side effect, But the actual risk was 53 percent.

Hanoch said: “These were really interesting results. By presenting participants with a wide range of medical scenarios, our findings lend support to a growing body of evidence regarding unrealistic optimism. These results suggest that clinicians may need to ensure that patients do not underestimate risks of medical interventions, and that they convey realistic expectations about the benefits that can be obtained with certain procedures. It would be good to carry out further studies on a larger population and also explore if and how clinicians can help manage expectations.”