Who uses decision aids? Subgroup analyses from a randomized controlled effectiveness trial of two prostate cancer screening decision support interventions.

OBJECTIVE: To examine who reported using unsolicited prostate cancer screening decision aids distributed as part of a randomized controlled trial, whether reported use varied by type of aid (video or pamphlet), and what affect reported use had on study outcomes. METHODS: A total of 1,152 men aged 50 and older from four medical facilities in the United States were randomly assigned to pamphlet, video or usual care (control). Materials were mailed 2 weeks prior to clinic appointments in general internal medicine. Outcomes were assessed by phone survey 1 week after appointments. Analyses examined the reported use of materials by study group, the association between patient characteristics and reported use, and the impact of reported use (adjusting for patient characteristics) on a 10-item knowledge index. RESULTS: Fifty-six percent of those randomized to receive the video and 50% of those randomized to receive the pamphlet reported using the materials. Reported use of the video was higher for patients who had greater than a high school education (OR 1.73), were married (OR 2.20), and reported no prior abnormal prostate cancer screening test results (OR 3.39). Reported use of the pamphlet did not vary by patient characteristics. In intent-to-treat analyses (ignoring reported use), individuals randomized to the video and pamphlet groups had significantly higher knowledge scores relative to the control group (7.44, 7.26 and 6.90 respectively). Adjusting for reported use modestly increased the estimated differences across treatment groups but did not substantially change conclusions about the relative effects of these aids on knowledge. CONCLUSIONS: Only half of men receiving unsolicited prostate cancer screening decision aids before a visit reported using the aids, and who reported using them varied by type of aid. Efforts to broadly implement decision aids may need to offer a variety of approaches, and incorporate creative strategies to enhance reaching all population subgroups.