Different Ways to Describe the Benefits of Risk-Reducing Treatments

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The summary below is from the full report titled "Different Ways to Describe the Benefits of Risk-Reducing Treatments. A Randomized Trial." It is in the 19 June 2007 issue of Annals of Internal Medicine (volume 146, pages 848-856). The authors are P.A. Halvorsen, R. Selmer, and I.S. Kristiansen.

What is the problem and what is known about it so far?

Previous research has shown that opinions about a treatment can differ depending on how its outcome is described. Describing the effect of a treatment to prevent a disease is tricky. Many people would never get the disease even without taking the medicine. In a person who would become ill without the medicine, the treatment may either totally prevent the disease or postpone it to a later stage in the person's life. Other people will get the disease at the same time as they would without treatment. A common way to describe the effect of a treatment is to define the number of people who must be treated to prevent 1 person from getting the disease. However, this method does not take into account that treatment delays—as opposed to prevents—disease in some people.

Why did the researchers do this particular study?

To determine how people decide whether to take medications to prevent disease.

Who was studied?

2754 adults born in certain years who lived in 1 county in Norway. Of these adults, 81% answered the survey.

How was the study done?

The authors asked about treatments to prevent 2 conditions: heart attacks and hip fractures. They sent surveys regarding a treatment to prevent heart attacks to 1754 persons. The authors randomly chose people to receive 1 of 3 surveys. Each survey asked whether the person would consent to the treatment. One survey described the outcome of treatment as the number of people who had to be treated for 5 years for 1 person to avoid a heart attack. Another survey described the outcome as all persons living 2 months longer before having a heart attack. The third survey stated that the treatment would delay a heart attack for 8 months for one quarter of the people receiving treatment and the rest would have no benefit from taking the medicine. The effect of the treatment was the same in each survey, although the effect was described differently. The authors used the same method to survey people about treatments for hip fractures.

What did the researchers find?

People were more likely to consent to both interventions when the survey described the outcome as the number of patients who needed to be treated to prevent 1 heart attack or hip fracture. People were least likely to consent to treatment when the description was a small delay for all persons. The consent rate was in between when the description was a large delay for a small number of people.

What were the limitations of the study?

Answering a survey is not the same as actually taking a medication to prevent disease.

What are the implications of the study?

The way that a physician describes the outcome of a preventive treatment may affect the likelihood that a person will consent to the treatment. Patients need to ask questions about the outcome of a treatment and perhaps ask their doctor to describe it in several different ways.