Background: Anticoagulant or antiplatelet agents have been shown to prevent ischemic stroke in patients with atrial ﬁbrillation. The quality of warfarin control was assessed by time in therapeutic range (TTR). However, the association between TTR and stroke risk remains unclear.
Objectives: A systematic review and meta-analysis was conducted to evaluate the association between anticoagulant agents and stroke, bleeding, and mortality. The cut-point of TTR was also evaluated.
Methods: PubMed, the Cochrane Library, and the ClinicalTrials.gov registry were searched for studies published before April 2016. Individual effect sizes were standardized, and a meta-analysis was conducted to calculate a pooled effect size using a random-effects models. Secondary outcomes included the risk of bleeding or mortality and the pattern of TTR.
Results: A total of 12 trials with 154,378 participants were reviewed. Significant risk of stroke reduction was observed in the anticoagulant groups (odds ratio 0.72, 95% confidence interval 0.67 to 0.78; I2 0%). The anticoagulant-treated group had higher risk of bleeding but this was not significant. The mortality rate was lower in the anticoagulant-treated group, but not significantly different. According to these trials, the TTR ranged from 30% to 100%. There was no consistent cut-point for the definition of high or low TTR. The results show that higher TTR was associated with lower risk of stroke and mortality. The trend of bleeding rate was higher in the low TTR group.
Conclusions: The results suggest that use of anticoagulant agents and maintenance of higher TTR can effectively reduce the risk of stroke and mortality. The bleeding rate was not significantly higher when anticoagulant agents were used.