Table 1. Answers to selected questions on the questionnaire*.
| Block | No. | Question | Control arm | Intervention arm | p-value | ||
|---|---|---|---|---|---|---|---|
| Start of trial | 6 months later | Start of trial | 6 months later | ||||
| Patient‘s self-asssessment of knowledge | 0.62 | ||||||
| Very good | 11% | 9% | 8% | 6% | |||
| Good | 51% | 73% | 45% | 78% | |||
| Fair | 32% | 16% | 39% | 15% | |||
| Inadequate | 4% | 1% | 7% | 0% | |||
| Individual situation | 1 | Indication for oral anticoagulation known | 87% | 92% | 99% | 99% | 0.06 |
| 2 | Risk lowering | 79% | 85% | 81% | 94% | 0.03 | |
| 3 | Treatment duration known | 69% | 82% | 75% | 94% | 0.01 | |
| 4 | Frequency of checking known | 87% | 89% | 78% | 93% | 0.08 | |
| 5 | INR (or Quick test) target range known | 52% | 71% | 57% | 83% | 0.04 | |
| INR-relatedknowledge | 6 | Foods containing vitamin K | <0.001 | ||||
| Types of cabbage | 69% | 71% | 72% | 94% | |||
| Lettuce | 37% | 49% | 50% | 75% | |||
| Spinach | 48% | 48% | 48% | 72% | |||
| Onions | 8% | 13% | 12% | 48% | |||
| 7 | Dietary recommendation for regular vitamin K intake | 34% | 43% | 30% | 70% | <0.001 | |
| 8 | What to do about forgotten doses | 13% | 16% | 14% | 57% | <0.001 | |
| 9 | Interactions with oral anticoagulation | 0.007 | |||||
| Ginkgo biloba | 4% | 6% | 5% | 17% | |||
| Non-prescription drugs | 22% | 25% | 18% | 38% | |||
| Fasting, weight-loss diets | 16% | 17% | 13% | 28% | |||
| Gastroenteritis | 21% | 24% | 15% | 50% | |||
| Fever | 6% | 14% | 4% | 34% | |||
| Practical knowledge | 10 | Paracetamol is the safest analgesic available without a prescription | 22% | 27% | 19% | 64% | <0.001 |
| 11 | Knowing that insufficient anticoagulation cannot be felt | ||||||
| 12 | Recognition of emergencies and complications | <0.001 | |||||
| Painful bumps under the skin, whether discolored or not | 23% | 34% | 30% | 56% | |||
| Sudden speach impairment | 46% | 52% | 51% | 76% | |||
| Black (tarry) stool | 34% | 54% | 40% | 79% | |||
| Limb weakness | 22% | 35% | 25% | 51% | |||
| 13 | Knowing when it is important to state that one is taking an oral anticoagulant | 0.007 | |||||
| At the dentist‘s | 90% | 87% | 90% | 97% | |||
| At the pharmacy | 26% | 21% | 28% | 52% | |||
| Before getting an injection | 44% | 40% | 43% | 64% | |||
| When a new drug is prescribed | 54% | 52% | 54% | 64% | |||
| Before undergoing any invasive medical procedure | 90% | 88% | 86% | 90% | |||
*The p-values relate to the hypothesis of an effect of the intervention in question in the hierarchical model; the dependent variable for the patients‘ self-assessment of knowledge was a score on the 1-to-4 scale; for other questions, the probability of a correct answer was modeled.
INR, international normalized ratio.