Are people's perceived risks of medicine side effects affected by the words we use to describe them?

ISRCTN ISRCTN39432352
DOI https://doi.org/10.1186/ISRCTN39432352
Secondary identifying numbers York-Leeds CRUK9
Submission date
13/03/2014
Registration date
23/04/2014
Last edited
16/01/2017
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Cancer
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data

Plain English summary of protocol

Background and study aims
Within the European Union (EU), pharmaceutical licence holders have to make public information on potential adverse effects associated with medicines. EU guidance is that this information should include estimated frequencies of any effects; however, there is uncertainty about the most effective way to do this. In the UK two influential organisations, the MHRA and NICE, have advocated using risk expressions that combine a numerical estimator and a verbal term: e.g. "this side effect is common (it may affect more than 1 in 100 people)". However, there is no apparent evidence to support this recommendation and a concern is that the use of the verbal terms (very common, common, uncommon, rare, very rare) may lead to increased risk estimates. There is also a lack of evidence about the risk qualifier terms. In this case, the recommendation is to use the term 'may', although 'will' would seem more accurate.

Who can participate?
Adults accessing the study via two pages (http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/cancer-drugs/paclitaxel AND http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/cancer-drugs/) on the Cancer Help UK website.

What does the study involve?
Participants are randomly allocated to receive information on five side effects of Taxol using either a numerical term only or a combined numerical and verbal term, and using either the word 'will' or the word 'may'. Participants read the information and then estimate the frequency of the 5 side effects and of any side effect occurring. They also give estimates of the severity and 'harmfulness' of the side effects, using 5 Likert scales. Finally participants complete 8 questions intended to measure their numeracy skills.

What are the possible benefits and risks of participating?
Potential benefits of participating are to have a clearer understanding of the risks associated with the medicine, Taxol. There are no risks associated with taking part - just the time given to completing the questionnaire.

Where is the study run from?
The study is the result of a collaboration between researchers at the Universities of York and Leeds, and the website Cancer Help UK (owned by the charity Cancer Research UK). The data are held on a database at the University of Leeds. The PI, Dr Peter Knapp, is based at the University of York, UK.

When is the study starting and how long is it expected to run for?
January 2013 to April 2014

Who is funding the study?
1. University of Leeds (UK)
2. University of York (UK)

Who is the main contact?
Dr Peter Knapp
peter.knapp@york.ac.uk

Contact information

Dr Peter Knapp
Scientific

Department of Health Sciences
University of York
York
LS10 9DD
United Kingdom

Phone +44 (0)1904 321675
Email peter.knapp@york.ac.uk

Study information

Study designFactorial trial (2x2) with concealed random allocation of individual participants
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Other
Study typeOther
Participant information sheet There is no PIS - that was approved by the REC. There is brief information on the website before people agree to take part. By agreeing to take part, people are confirming that they have received sufficient information about the study.
Scientific titleWhat is the effect of two framing variables on perceived risks associated with the medicine Taxol?
Study acronymCRUK9
Study objectivesThat participants' risk perceptions will not be influenced by two potential framing influences: first, providing frequency information using numbers alone or a combination of number and words; second, using different verbal qualifiers to convey risk.
Ethics approval(s)University of Leeds, Institute of Psychological Sciences research Ethics Committee, 22/06/2012, ref: 12-0127
Health condition(s) or problem(s) studiedCancer
InterventionInformation. (Risk frequency information presented in one of four ways).

There are four arms to the trial. Participants read the information about the medicines and then answer some questions about it. That is, 'follow-up' is immediate.
In all four arms of the trial participants receive information about 10 potential side effects of Taxol - the way that that risk is expressed varies across the four trial conditions.

The side effects:

1. May affect more than 1 in 10 people.
2. Very common: may affect more than 1 in 10 people
3. Will affect more than 1 in 10 people.
4. Very common: will affect more than 1 in 10 people.

(The incident rate bands vary according to the SE being portrayed).

The trial is evaluating the effect of adding verbal risk terms to the numerical information. Also, the use of the terms 'may' and 'will' to convey risk.
Intervention typeOther
Primary outcome measure1. Estimated frequency of any side effect occurring
2. Estimates frequency of 5 individual side effects
Secondary outcome measures1. Estimated severity and degree of harm from the side effects
2. Participants' numeracy
Overall study start date01/01/2013
Completion date01/04/2014

Eligibility

Participant type(s)Patient
Age groupAdult
SexBoth
Target number of participants318
Key inclusion criteriaAdults (aged 16 or over) accessing the study via two pages (http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/cancer-drugs/paclitaxel AND http://www.cancerresearchuk.org/cancer-help/about-cancer/treatment/cancer-drugs/) on the Cancer Help UK website.
Key exclusion criteriaDoes not meet inclusion criteria
Date of first enrolment01/01/2013
Date of final enrolment01/04/2014

Locations

Countries of recruitment

  • England
  • United Kingdom

Study participating centre

University of York
York
LS10 9DD
United Kingdom

Sponsor information

University of York (UK)
University/education

Department of Health Sciences
York
LS10 9DD
England
United Kingdom

ROR logo "ROR" https://ror.org/04m01e293

Funders

Funder type

University/education

University of Leeds (UK)
Private sector organisation / Universities (academic only)
Location
United Kingdom
University of York
Government organisation / Universities (academic only)
Alternative name(s)
The University of York, York, Ebor, Universitas Eboracensis
Location
United Kingdom

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryNot provided at time of registration
Publication and dissemination planNot provided at time of registration
IPD sharing plan

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Results article results 01/04/2016 Yes No

Editorial Notes

16/01/2017: Publication reference added.