Change in VKA control measures reported in studies published between 2000–2003 and 2004–2013
| Variable | Studies published in 2000–2003 (N=23) n (%) | Studies published in 2004–2013 (N=125) n (%) | p Value* |
|---|---|---|---|
| Number of measures reported (mean±SD) | 1.48±0.79 | 2.23±1.43 | 0.02 |
| 1 | 15 (65.2) | 51 (40.8) | |
| 2 | 6 (26.1) | 35 (28.0) | |
| 3 | 1 (4.3) | 15 (12.0) | |
| 4 | 1 (4.3) | 12 (9.6) | |
| 5 | 0 | 8 (6.4) | |
| 6 | 0 | 3 (2.4) | |
| 7 | 0 | 1 (0.8) | |
| ≥2 | 8 (34.8) | 74 (59.2) | 0.05 |
| Percentage of time in range (INR=2–3) | 15 (65.2) | 102 (81.6) | 0.14 |
| Proportion of INR tests in range (INR=2–3) | 4 (17.4) | 20 (16.0) | 0.89 |
| Mean/median INR | 7 (30.4) | 31 (24.8) | 0.76 |
| Mean/median VKA dose | 1 (4.3) | 16 (12.8) | 0.42 |
| Frequency of INR monitoring | 2 (8.7) | 36 (28.8) | 0.08 |
| INR variability | 0 | 8 (6.4) | 0.46 |
| INR testing interval | 4 (17.4) | 26 (20.8) | 0.98 |
| Proportion of patients in/out of range† | 1 (4.3) | 28 (22.4) | 0.09 |
| Other‡ | 0 | 12 (9.6) | 0.26 |
*p Value for the comparison of studies published in 2000–2003 vs 2004–2013.
† For example, point prevalence, proportion of patients in range >50% of time or proportion of patients with ≥50% of INR measures <3.0.
‡Other measures include: number of dosage changes; INR measure after a previously subtherapeutic or supratherapeutic INR; proportion of patients with ≥1INR measure below range after reaching an adequate INR; number of days until the next INR measure after an extreme measure; proportion of days with treatment stability (two consecutive INR measures in range); days to reach a therapeutic INR; mean time until stable (6 months within target INR range); minimum and maximum INR values per patient.
INR, international normalised ratio; VKA, vitamin K antagonist.