The impact of within-visit and pre-visit decision aids for localized prostate cancer on patient knowledge.

151 Background: Decision aids (DAs) for prostate cancer treatment can improve knowledge and reduce decisional conflict, but the relative effect of pre-visit and within-visit DAs is not known, and effect sizes for minority populations has not been estimated. Methods: We conducted a 3-arm, patient-level-RCT in specialty urology and radiation oncology practices in Ohio, South Dakota, and Alaska, test the effect of pre-consultation and with-in consultation decision aids on patient knowledge immediately after specialty consultation compared to usual care. We used linear regression to estimate effects of each intervention arm, including the respective standard error, two-sided 95% confidence interval, and two-sided P value for testing the study’s hypotheses. Results: 103 patients were recruited and randomized to receive either the pre-visit decision aid, within-visit decision aid, or neither decision aids (usual care). In 2017 and 20018, we accrued similar numbers of men to pre-consultation aid (n = 37), during-consultation aid (n = 33) and usual care arms, respectively (n = 33). The median (range) age in years was 64 [49, 81]; 67.6% were White, 15.7% were Black or African American, 16.7% were American Indian or Alaska Native, and 1% were not reported. 47.6%, 45.6%, and 6.8% had a baseline clinical stage of T1, T2, and T3, respectively. The median [range] prostate specific antigen (PSA) was 8.0 [2.4, 53.7]. There were no clinically notable imbalances. We obtained usable data on 102 of the 103 patient-participants. The pre-visit decision aid arm showed a mean knowledge effect of 0.694 (0.636, 0.753). The within-visit decision arm showed a very similar mean knowledge effect of 0.686 (0.625, 0.748). The usual care arm showed a mean knowledge effect of 0.644 (0.582,0.705). The linear regression model showed, that, compared with usual care, neither intervention effect achieved statistical significance in the primary analysis (p = 0.24, 0.330, for pre-visit and within-visit, respectively). Conclusions: Modest knowledge gains of pre-visit and during-visit decision aids for prostate cancer treatment were not statistically significant. Clinical trial information: NCT03182998 .