Eleven trials were available in IPD format with data for 6,417 participants and 12,800 person-years of follow-up. IPD were unobtainable from a further 10 eligible trials.
There was a significant reduction in thromboembolic events in the self-monitoring group (HR 0.51, 95% CI 0.31 to 0.85), but not for major haemorrhagic events (HR 0.88, 95% CI 0.74 to 1.06) and death (HR 0.82, 95% CI 0.62 to 1.09). Participants younger than 55 years showed a large reduction in thrombotic events (HR 0.33, 95% CI 0.17 to 0.66, substantial heterogeneity I2=52%), as did participants with mechanical heart valves (HR 0.52, 95% CI 0.35 to 0.77, no substantial heterogeneity).
Statistically significant interactions between effectiveness in reducing thromboembolic events and IPD covariates were found for age, indication and self monitoring.