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A randomised controlled trial of the effects of a web based Prostate Specific Antigen decision explorer, Prosdex
ISRCTN ISRCTN48473735
DOI 10.1186/ISRCTN48473735
ClinicalTrials.gov identifier
EudraCT number
Public title A randomised controlled trial of the effects of a web based Prostate Specific Antigen decision explorer, Prosdex
Scientific title
Acronym PROSDEX
Serial number at source RCUC062 C6475/A7490
Study hypothesis To evaluate the effects on men of a web-based Prostate Specific Antigen (PSA) decision-aid, Prosdex. The objectives are to assess the effect of Prosdex on:
1. Knowledge of PSA and prostate cancer-related issues
2. Attitudes to testing
3. Decision conflict
4. Anxiety
5. Intention to undergo PSA testing
6. Uptake of PSA testing

In addition, a mathematical simulation model of the effects of Prosdex on subsequent resource use and health outcomes will be developed. The null hypothesis, based on the principal outcome, knowledge, is that Prosdex would not have an effect on knowledge of PSA and prostate cancer-related issues.
Lay summary Not provided at time of registration
Ethics approval Approval received from the South East Wales Research Ethics Committee, Panel D on the 8th January 2007 (ref: 06/WSE04/138).
Study design Randomised controlled trial
Countries of recruitment United Kingdom
Disease/condition/study domain PSA decision aids, prostate cancer
Participants - inclusion criteria Men between ages of 50 and 75
Participants - exclusion criteria 1. Previous PSA test or prostate cancer
2. Inability to access internet
3. Men who are known to be unable to read English
4. Serious uncontrolled medical conditions or concurrent medical illness likely to compromise life expectancy
5. Severe mental illness or dementia
Anticipated start date 01/10/2007
Anticipated end date 01/06/2008
Status of trial Completed
Patient information material
Target number of participants 600
Interventions A web-based PSA decision aid, Prosdex: it will require a password for access and will generate the online questionnaire.

Intervention group:
Group one: Men in intervention group one will be asked to log onto and view the website, either in their own homes or in another setting of their choice.
Group two: The second intervention group will receive a paper document comprising the text of the website. This enables evaluation of the Prosdex features (e.g. video clips and the structured decision support) that go beyond the mere presentation of the text content.

Control group:
Group three: In the first control group, men, after inserting their password, will be asked to complete the online questionnaire without viewing Prosdex.
Group four: The second control group will not initially be given the details of the study website.
Primary outcome measure(s) Knowledge of PSA and prostate cancer-related issues: this will be assessed using a set of knowledge questions, used in an earlier evaluation of a brief paper-based leaflet about PSA testing, which showed an ability to discriminate between intervention and control groups.

The primary outcome, knowledge, will be measured immediately after the intervention: that is, men will be directed, automatically, from the Prosdex website to the online questionnaire. Men in the second intervention group and the first control group will also be asked at T0 to log onto the online questionnaire.
Secondary outcome measure(s) The secondary outcome measures will be measured immediately after the intervention: that is, men will be directed, automatically, from the Prosdex website to the online questionnaire.

1. Attitudes to testing: this will use a 12-item scale developed and used in the same evaluation of a brief paper-based leaflet about PSA testing
2. Decision conflict: this scale measures patients’ confidence or uncertainty (‘conflict’) about whether they feel their choice is the best for them personally. It has acceptable validity and reliability (internal consistency alpha coefficients range from 0.78 - 0.89; test-retest reliability coefficients exceed 0.80). Given the nature of the decision about having a PSA test, with a high degree of uncertainty likely to affect decision making, it is important to use this, the most widely used outcome measure in decision aid studies
3. Anxiety: This will be assessed using the short form Spielberger questionnaire for ‘state’ anxiety, validated and shown to be responsive in our earlier studies of shared decision making and risk communication
4. Intention to undergo PSA testing: this will be assessed using a single item question, with Likert-like response scale, which has also been used in our earlier evaluation of a brief paper-based leaflet about PSA testing
5. Uptake of the PSA test: measured six months after the intervention

In addition, based on these results, a mathematical simulation model of the effects of Prosdex on subsequent resource use and health outcomes will also be developed. Secondary outcomes one to four, in addition to the primary outcome, knowledge, will be gathered from the online questionnaire.

After the six month PSA testing, all the men will be asked to to complete the online questionnaire again.
Sources of funding Cancer Research UK (UK) (ref: C6475)
Trial website
Publications 1.2010 results in http://www.ncbi.nlm.nih.gov/pubmed/20507844
2. 2010 results in http://www.ncbi.nlm.nih.gov/pubmed/20693148
Contact name Prof  Glyn  Elwyn
  Address Department of Primary Care and Public Health
Centre for Health Sciences Research
Cardiff University
2nd Floor, Neuadd Meirionnydd
Heath Park
  City/town Cardiff
  Zip/Postcode CF14 4YS
  Country United Kingdom
  Email elwyng@cardiff.ac.uk
Sponsor Cardiff University (UK)
  Address Research and Commercial Division
7th floor, McKenzie House
30 - 36 Newport Road
  City/town Cardiff
  Zip/Postcode CF24 0DE
  Country United Kingdom
  Email DaviesKP2@cf.ac.uk
  Sponsor website: http://www.cardiff.ac.uk/index.html
Date applied 21/03/2007
Last edited 15/12/2011
Date ISRCTN assigned 26/04/2007
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