A total of 36 studies met the inclusion criteria (number of patients not reported): 22 were restricted to patients with AF and used for primary analyses; and 14 included mixed populations and were used for secondary analyses. Statistical heterogeneity was present for all pooled estimates.
The pooled overall mean time for AF patients in the INR range of 2.0 to 3.0 was 61.3 per cent (95% CI: 58.8, 63.8). Pooled mean time in INR was 59.1 per cent (95% CI: 55.5, 62.8) for infrequent monitoring and 64.3 per cent (95% CI: 60.5, 68.0) for frequent monitoring; the difference between the groups was not significant. Significantly more time was spent in range in specialist care settings than usual care 11.3 per cent (95% CI: 0.1, 21.7). Naïve OAC users spent less time in range 56.5 per cent (95% CI: 45.5, 67.5) than existing users 61.2 per cent (95% CI: 57.2, 65.2); the difference between the groups was not significant.