Descriptive statistics for outcome measures (displayed as estimated marginal means (unless otherwise indicated) with 95% CIs) immediately post intervention, stratified by health literacy and study arm
| Outcome measure | Study arm | Interaction p values | |||||
| Preparation video | Choosing Wisely questions | Both interventions | Control | Video × health literacy | Questions × health literacy | Video × questions × health literacy | |
| Limited health literacy | (n=162) | (n=155) | (n=165) | (n=174) | |||
| Primary outcomes | |||||||
| Self-efficacy to ask questions and be involved in health decision-making (0–100) | 85.0 (83.7, 86.4) | 85.8 (84.4, 87.2) | 84.0 (82.6, 85.3) | 84.7 (83.4, 86.0) | 0.074 | 0.70 | 0.051 |
| Intention to engage in SDM (0–6) | 5.0 (4.9, 5.1) | 4.9 (4.8, 5.0) | 5.2 (5.0, 5.3) | 4.9 (4.7, 5.0) | 0.85 | 0.61 | 0.20 |
| Secondary outcomes | |||||||
| Intention to follow treatment plan without further questioning (0–10) | 7.3 (6.7, 7.5) | 7.6 (7.3, 7.9) | 7.5 (7.2, 7.7) | 7.5 (7.3, 7.8) | 0.48 | 0.23 | 0.72 |
| Accurate knowledge of patient’s shared decision-making rights (proportion) | 0.83 (0.79, 0.87) | 0.84 (0.80, 0.88) | 0.79 (0.74, 0.84) | 0.83 (0.79, 0.87) | 0.13 | 0.46 | 0.42 |
| Positive attitude towards SDM (proportion) | 0.50 (0.42, 0.58) | 0.51 (0.43, 0.58) | 0.50 (0.42, 0.57) | 0.44 (0.36, 0.51) | 0.31 | 0.93 | 0.99 |
| Preparedness for SDM (1–5) | 3.9 (3.8, 4.1) | 4.0 (3.8, 4.1) | 4.0 (3.8, 4.1) | (n/a) | 0.35* | ||
| Adequate health literacy | (n=194) | (n=194) | (n=186) | (n=209) | |||
| Primary outcomes | |||||||
| Self-efficacy to ask questions and be involved in health decision-making (0–100) | 84.5 (83.2, 85.7) | 84.0 (82.7, 85.2) | 85.6 (84.4, 86.9) | 84.3 (83.1, 85.5) | |||
| Intention to engage in SDM (0–6) | 5.1 (5.0, 5.2) | 5.0 (4.9, 5.1) | 5.2 (5.1, 5.3) | 4.8 (4.7, 4.9) | |||
| Secondary outcomes | |||||||
| Intention to follow treatment plan without further questioning (0–10) | 6.8 (6.5, 7.1) | 7.1 (6.8, 7.3) | 6.7 (6.4, 7.0) | 7.2 (6.9, 7.4) | |||
| Accurate knowledge of patient’s shared decision-making rights (proportion) | 0.87 (0.83, 0.92) | 0.91 (0.86, 0.94) | 0.91 (0.87, 0.95) | 0.87 (0.83, 0.92) | |||
| Positive attitude towards SDM (proportion) | 0.57 (0.50, 0.64) | 0.63 (0.56, 0.70) | 0.62 (0.55, 0.70) | 0.51 (0.44, 0.57) | |||
| Preparedness for SDM (1–5) | 3.8 (3.7, 4.0) | 3.9 (3.8, 4.0) | 4.0 (3.9, 4.2) | (n/a) | |||
*P value represents the two-way interaction of health literacy×intervention (three levels coded as video only, questions only or both).
SDM, shared decision-making.