Comparison of Explicit, Implicit and no Values Clarification Decision Aids for Men Considering Prostate Cancer Screening

Study Overview
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Brief Summary
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The investigators aim at comparing the perceived clarity of personal values in men considering PSA screening using decision aids with no VCM versus an implicit VCM versus an explicit VCM. This study will add to the body of evidence on the role of decision aids to support health preference-sensitive choices and provide further insight on the impact of different methods for eliciting people's values embedded within a decision aid.

Detailed Description
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PSA test to screen for prostate cancer is considered a preference sensitive decision, meaning it does not only depend on what is best from a medical point of view, but also on patient values. Decision aids are evidence-based tools which showed to help people feel clearer about their values, therefore it has been advocated that decision aids should contain a specific values clarification method (VCM). VCM may be either implicit or explicit but the evidence concerning the best method is scarce. We aim at comparing the perceived clarity of personal values in men considering PSA screening using decision aids with no VCM versus an implicit VCM versus an explicit VCM.

Official Title
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Comparison of Explicit Values Clarification Method (VCM), Implicit VCM and no VCM Decision Aids for Men Considering Prostate Cancer Screening: Protocol of a Randomized Trial

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Other: Decision aid with implicit values clarification method (booklet or website)
* Other: Decision aid with explicit values clarification method (booklet or website)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adult men (50 - 69 years); men with average risk for prostate cancer; willing and able to provide written informed consent. Exclusion Criteria: unable to understand written Portuguese.

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 69 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel three group (1:1:1): (i) decision aid with information only (Control), (ii) decision aid with information plus an implicit VCM, (iii) decision aid with information plus an explicit VCM.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: decision aid with information only (control)<br>decision aid with information only, without values clarification method (VCM) | |
| Active Comparator: decision aid with implicit VCM<br>decision aid with information plus an implicit VCM | Other: Decision aid with implicit values clarification method (booklet or website)<br>* The intervention will be an informative evidence-based material in the format of a booklet or website concerning prostate cancer screening. The values clarification method will be a grid where statements about the subject will be presented (decision aid with implicit VCM).<br>|
| Active Comparator: decision aid with explicit VCM<br>decision aid with information plus an explicit VCM | Other: Decision aid with explicit values clarification method (booklet or website)<br>* The intervention will be an informative evidence-based material in the format of a booklet or website concerning prostate cancer screening. The values clarification method will be a a grid where statements about the subject will be presented and men should indicate what statements they identify with (decision aid with explicit VCM).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Perceived clarity of personal values | 3-item subscale of the Decisional Conflict Scale. Items are given a score of 0 (strongly agree) to 4 (strongly disagree). Items are: a) summed; b) divided 3; and c) multiplied by 25. Scores range from 0 [feels extremely clear about personal values] to 100 [feels extremely unclear about personal values]. | immediately after the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Decisional Conflict | Decisional Conflict Scale (16-item). Items are given a score of 0 (strongly agree) to 4 (strongly disagree). Items are: a) summed; b) divided 16; and c) multiplied by 25. Scores range from 0 [no decisional conflict] to 100 [extremely high decisional conflict]. | immediately after the intervention | 
| % of patients with preference to undergo PSA screening (screening intention; questionnaire) | Intention to undergo prostate cancer screening with PSA: questionnaire - single question about intention to be screened with PSA, using a 5 point-Likert scale (ranging from strongly disagree to strongly agree; intention to undergo PSA screening will be considered positive if the respondent replies with agree or strongly agree). % of patients with preference to undergo PSA screening. | before and immediately after the intervention | 
| % of patients who underwent PSA screening (questionnaire) | Self-reported PSA screening. Questionnaire - single question. Men will report wether they have or have not underwent PSA screening after the intervention. % of patients who underwent PSA screening | 6 months after the intervention |