Understanding research and risk: what do those media headlines really mean?

Each week we are surrounded by stories in the media about new medical findings that often leave us confused. Research may be presented in technical language which makes it difficult for us to understand the findings. How do we make sense of what we see and hear? Which results are important? And how do we know what – and whom – to believe?

Medical research studies are important because they help to provide information on health and how to treat disease. Studying large groups of people gives researchers the opportunity to find out more about the risks and benefits of a particular treatment. Some studies aim to find out what causes disease, and how to avoid getting sick, while others may be searching for new treatments or focusing on improving current treatments. Sometimes research results may seem confusing. For example, the US Government-funded Women’s Health Initiative (WHI) reports on the benefits and risks of hormone therapy were confusing to many women. In order to help make sense of what we read or hear, it can be helpful to understand how the research was conducted and ask yourself a few questions about what it means to you.

Questions to help you understand if a study is relevant to you

Who took part in the study? Were people chosen randomly for the study or did they volunteer? Did participants already have symptoms or were they part of the general community? Was it a large study? What kind of treatment was used and for how long? If a new treatment was being tested, were there side effects?

Can the findings be generalised to the community, and more importantly, to you? Are the results easy to understand? Were there factors that may have influenced the findings? Who funded the research? Was the study published in a scientific journal? Is the source reporting the study results reliable and well able to interpret scientific data?

Understanding risk

Human nature sees us focus on, and remember, the negative far more than we would the positive. We may hear that a treatment causes a three-fold – or a 300 per cent – increase in stroke. This increase seems staggering. But is it? For example, the article may not tell you that for every 10,000 people not taking this treatment, there are two strokes. So, a three-fold increase in the group taking the treatment simply means six strokes. Six out of 10,000, compared to two out of 10,000. Our perception of risk may be based on other factors, such as anecdotal evidence (when we hear about something from someone else) or emotional factors not reflected in fact. If a risk seems a long time away then we may not pay it as much attention as we would if it was going to happen soon. Often we think, “that won’t happen to me, that kind of thing only happens to other people”. Explanations are needed to help understand the numbers, so the benefits and the likelihood of side effects from a treatment can be understood, and ultimately the risk of continuing – or stopping – can be an informed decision.

Absolute and relative risk

Often you will hear risk referred to as absolute or relative.

Absolute risk

An absolute risk is the actual number of health events that resulted or were prevented by the treatment. If 50 heart attacks were found in 10,000 people taking the treatment and 75 heart attacks in a similar group taking the placebo, this means that for every 10,000 people on treatment, 25 heart attacks would be prevented. This is absolute risk. Absolute risk may be easier to understand when applying medical research results to your own healthcare decisions. In the WHI example of combined hormone therapy with oestrogen and progestin the absolute risk, or actual increased risk, is 7 more heart attacks per year per 10,000 women, or less than 1/1000 women receiving treatment per year. Absolute risk may be easier to understand as it gives actual numbers.

Relative risk

Relative risk may be used by researchers in comparing the likelihood that a person taking a new treatment will have a heart attack to the likelihood that a person taking a placebo (dummy or sugar pill) will have one. A relative risk between two groups is usually shown as a ratio or a percentage. For example, in the WHI trial overall there were 30 heart attacks per 10,000 women per year in the placebo group and 37 in the combined oestrogen and progestin hormonetreated group, giving a relative risk of 37 compared to 30 for hormone treatment (37 ÷ 30 which equals a relative risk of 1.2). This can also be expressed as an increase of 23 per cent, which sounds alarming. Unfortunately, figures such as these are what the media tends to focus on.

How these numbers are presented to you may sway how you feel about the finding and affect whether you change your behaviour as a result.

Imagine a department store catalogue sale. Which do you find more eye-catching? Save 50 per cent or save $50? Put simply, some people respond more to numbers, others to percentages or ratios.

What does the risk mean to me?

Data looking at the risk of a disease is often reported as relative risk. In other words, the risks of taking a treatment is reported relative to, or compared to, the risks run by taking no treatment. However, this may not take into account the actual frequency of the condition in the untreated group.

For example, a relative risk of 2 – often reported in the media as ‘a doubling of risk’ – could describe something that increases the risk of a disease from 1 in a million to 2 in a million. Equally it could describe something that increases the risk of a disease from 4 in 10 people to 8 in 10 people. Both have a relative risk of 2. In this case absolute risk, or actual numbers, which takes into account the frequency of the condition, is a better method of presenting the results.

Remember, you need to weigh your choices available to you, based on best evidence obtained from medical research against:

• The resources available to you, including access to service and cost
• Your own personal values – does a particular treatment fit with your lifestyle and how you choose to take care of yourself?

The big picture

Medical research can take many years. The results of one study need to be confirmed by other researchers before they are accepted as general medical practice. Every step along the research path provides another clue — and leads to new questions being asked.

At the end of the day your health practitioner is bestplaced to talk you through any concerns you may have and can help you understand the results and what they mean for you. It is important to consider your individual risk of something occurring based on your own medical and family history.

Understanding that each drug or treatment carries risks as well as benefits will help you to ask questions of your health practitioner about the various options so that you can understand the risks and benefits that apply to you.

© 2007 The Jean Hailes Foundation for Women’s Health

Apart from fair dealing for the purposes of private study, research, criticism or review, as permitted under copyright legislation, no part may be reproduced or reused for any commercial purposes. 

Content updated November 29, 2007