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

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

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

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.

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.

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.

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).

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).

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].

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].

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.

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

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.

Baptista S, Heleno B, Teixeira A, Taylor KL, Martins C. 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. BMC Med Inform Decis Mak. 2020 Apr 29;20(1):78. doi: 10.1186/s12911-020-1094-3.