Judging the risk of medicine
Posted on 5 February 2015
In a study published in the journal Health Expectations (HE), he shows that a format using a combination of words, such as 'common' and 'rare', as well as numbers can increase the perceived risk of side effects compared with using numbers alone.
His research, using a trial design, looks at an aspect of the presentation of risk to patients - in this case about a medicine used in the treatment of cancer - and tests the format recommended by the European Medicines Agency (EMA) and endorsed by the MHRA (the Medicine and Healthcare products Regulatory Agency- the UK medicines regulator).
Dr Knapp said: "The EMA recommends that pharma companies use a certain format to convey information about the risk of side effects. Research by us shows this is mostly being followed which means many leaflets for medicines across Europe use this approach. However, there's no evidence to support their use and the HE paper shows that they lead to over-estimation of risk.
"It is a single study, testing one medicine, using an online recruitment method, but it’s a well designed study and is the first time that this format has been tested in this way."
Dr Knapp is a Senior Lecturer in Evidence-Based Decision Making in the Department of Health Sciences and the Hull York Medical School.
Peter Knapp, Peter H Gardner and Elizabeth Woolf. Combined verbal and numerical expressions increase perceived risk of medicine side-effects: a randomized controlled trial of EMA recommendations. Health Expectations 2015; doi: 10.1111/hex.12344
http://onlinelibrary.wiley.com/doi/10.1111/hex.12344/full.