Patients’ Baseline Characteristics by Treatment Group
| Characteristic | Morning (n = 109) | Evening (n = 108) |
|---|---|---|
| Sex, No. (%) | ||
| Male | 60 (55.0) | 51 (47.2) |
| Female | 49 (45.0) | 57 (52.8) |
| Age | ||
| Mean (SD), y | 72.7 (10.3) | 73.4 (10.3) |
| ≥80 y, No. (%) | 32 (29.4) | 31 (28.7) |
| Province, No. (%) | ||
| Alberta | 81 (74.3) | 85 (78.7) |
| British Columbia | 28 (25.7) | 23 (21.3) |
| Location, No. (%) | ||
| Urban | 86 (78.9) | 96 (88.9) |
| Rural | 23 (21.1) | 12 (11.1) |
| Indication for anticoagulation, No. (%) | ||
| Atrial fibrillation | 68 (62.4) | 63 (58.3) |
| DVT/PE | 31 (28.4) | 23 (21.3) |
| Mechanical valve | 11 (10.1) | 12 (11.1) |
| Other | 10 (9.2) | 17 (15.7) |
| Target INR range, No. (%) | ||
| 2.0-3.0 | 97 (89.0) | 97 (89.8) |
| 2.5-3.5 | 7 (6.4) | 11 (10.2) |
| Other | 5 (4.6) | 0 (0.0) |
| Warfarin use | ||
| Daily dose, mean (SD), mg | 5.0 (2.1) | 4.9 (2.2) |
| Duration of use, mean (SD), y | 7.9 (7.2) | 7.4 (6.8) |
| <6 months of use, No. (%) | 2 (1.8) | 4 (3.7) |
| Forget warfarin at least once per month, No. (%) | 8 (7.3) | 8 (7.4) |
| Warfarin administration time, No. (%) | ||
| >30 minutes before dinner | 15 (13.8) | 18 (16.7) |
| ≤30 minutes after dinner | 46 (42.2) | 49 (45.4) |
| >30 minutes after dinner | 13 (11.9) | 5 (4.6) |
| Bedtime | 32 (29.4) | 35 (32.4) |
| Varies | 3 (2.8) | 1 (0.9) |
| Stability of anticoagulation | ||
| Proportion of time within therapeutic range of INR (TTR), mean (SD) | 71.8 (20.2) | 72.6 (19.5) |
| Proportion of time outside of therapeutic range of INR, mean (SD) | 28.2 (20.2) | 27.2 (19.6) |
| TTR >75%, No. (%) | 53 (48.6) | 57 (52.8) |
| TTR <60%, No. (%) | 34 (31.2) | 24 (22.2) |
| Stability of anticoagulation | ||
| Maximum out of range INR, mean (SD) | 3.9 (1.0) | 4.0 (1.0) |
| Minimum out of range INR, mean (SD) | 1.6 (0.3) | 1.6 (0.3) |
| Percent of readings above range, mean (SD) | 14.0 (13.3) | 14.1 (13.9) |
| Percent of readings below range, mean (SD) | 18.0 (16.9) | 17.4 (16.7) |
| Randomization stratification, No. (%) | ||
| <50% INR values in range | 17 (15.6) | 17 (15.7) |
| 50%-80% INR values in range | 61 (56.0) | 61 (56.5) |
| >80% INR values in range | 31 (28.4) | 30 (27.8) |
| Days per week of high–vitamin K foods, No. (%) | ||
| <2 days | 44 (40.4) | 30 (27.8) |
| 2-5 days | 47 (43.1) | 57 (52.8) |
| >5 days | 18 (16.5) | 21 (19.4) |
| Variability of high–vitamin K foods, No. (%) | ||
| High | 44 (40.4) | 48 (44.4) |
| Low | 65 (59.6) | 60 (55.6) |
| Medications other than warfarin | ||
| Number, mean (SD) | ||
| Prescription medications | 4.8 (3.4) | 5.0 (3.3) |
| Over-the-counter medications | 0.6 (1.1) | 0.6 (1.1) |
| Vitamins/herbs | 1.9 (1.8) | 1.9 (2.2) |
| Prescription medications, No. (%) | ||
| Cardiovascular | 90 (82.6) | 94 (87.0) |
| Gastrointestinal | 32 (29.4) | 42 (38.9) |
| Diabetes | 14 (12.8) | 21 (19.4) |
| Pulmonary | 23 (21.1) | 14 (12.8) |
| Antiplatelet agents, No. (%) | ||
| Aspirin | 23 (21.1) | 25 (23.1) |
| Clopidogrel | 2 (1.8) | 5 (4.6) |
| Prasugrel | 1 (0.9) | 0 (0.0) |
| Dipyridamole/ticlopidine/ticagrelor | 0 (0.0) | 0 (0.0) |
INR = international normalized ratio; DVT = deep vein thrombosis; PE = pulmonary embolism; TTR = time within therapeutic range.