Table 2.
Anticoagulation practice and quality of control
| Clinical practice | Trial
|
Pooled data | |||||
|---|---|---|---|---|---|---|---|
| Peterson et al1 | Boston area2 | Stroke prevention3 | Connolly et al4 | Ezekowitz et al5 | |||
| Target range (INR equivalent) | 2.0-3.0 | 2.4-4.2 | 1.5-2.7 | 2.0-4.5 | 2.0-3.0 | 1.4-2.8 | Variable |
| Interval between tests (days)* | 31 | 28 | 21 | 30 | 21 | 30 | 21-30 |
| % time spent in range | 61 | 73 | 83 | 71 | 44 | 56 | 66 |
| % time below target range | 26 | 26 | 8 | 23 | 40 | 29 | 25 |
| % time above range | 13 | 1 | 9 | 5 | 16 | 15 | 9 |
| No (%) patients stopping warfarin | 30 (18) | 126 (38) | 21 (10) | 40 (19) | 49 (26) | 81 (29) | 316 (26) |
*
After initial period of stabilisation of international normalised ratio values, during which more frequent sampling was undertaken. Interval between tests includes tests for routine monitoring and more frequent repeat testing when values are outside range.