Fourteen RCTs (n=3,049) were included.
Four trials were judged to be of poor quality with unclear allocation concealment and no intention-to-treat analysis or masking.
Thromboembolic events.
There was a statistically significant reduction in thromboembolic events for self-monitoring patients compared with control patients (10 studies; OR 0.45, 95% CI: 0.30, 0.68). This result was not affected by the removal of the 4 low-quality studies (OR 0.41, 95% CI: 0.25, 0.70). Statistically significant reductions were also seen in the subgroups of studies with and without self-adjusted treatment.
Major haemorrhage.
There was a statistically significant reduction in major haemorrhage for self-monitoring patients compared with control patients (10 trials; OR 0.65, 95% CI: 0.42, 0.99). This result was no longer statistically significant when the 4 low-quality studies were excluded (OR 0.66, 95% CI: 0.37, 1.16). A statistically significant reduction was also seen in the subgroup of studies of self-monitoring only, but not for studies of self-monitoring with self-adjustment.
All-cause mortality.
There was a statistically significant reduction in the number of deaths from any cause for self-monitoring patients compared with control patients (6 studies; OR 0.61, 95% CI: 0.38, 0.98). This result was not affected by the removal of the 4 low-quality studies (OR 0.58, 95% CI: 0.36, 0.95). A statistically significant reduction was also seen in the subgroup of studies of self-monitoring with self-adjusted treatment, but not for the subgroup of studies of self-monitoring only.
Other outcomes.
Eleven studies reported improvements in the self-monitoring group in terms of the mean proportion of international normalisation ratios in range, with 6 studies reporting statistically significant improvements. Four studies reported an improvement in the proportion of time within ranges, of which two were statistically significant. Nine trials reported on minor haemorrhage, but these were not pooled because of statistically significant heterogeneity (P=0.01). The ratio of tests performed in the self-monitoring group compared with the control group ranged from 1.69 to 4.98, and this tended to increase with the duration of the study.