Frequency of adverse events in patients with poor anticoagulation: a meta-analysis
Key result
In patients taking oral anticoagulants, 44% of hemorrhages occurred when INRs were above the therapeutic range, and 48% of thromboemboli occurred when INRs were below the therapeutic range.
Why the study?
Does improved anticoagulation control prevent hemorrhagic and thromboembolic events in patients taking oral anticoagulants?
Population
45 studies pooling 71,065 patients taking oral anticoagulants with a target INR range.
Design
Meta-analysis
Authors
Discussion
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Implication
Intensified INR monitoring may avert many events; confirms time in therapeutic range as a pivotal, modifiable quality metric.
Study Design
Type
Meta-Analysis (n=71,065)
Structured PICO
Does improved anticoagulation control prevent hemorrhagic and thromboembolic events in patients taking oral anticoagulants?
P
Population
45 studies pooling 71,065 patients taking oral anticoagulants with a target INR range (lower limit 1.8-2, upper limit 3-3.5).
I
Intervention
Oral anticoagulants
O
Outcome
Proportion of hemorrhagic and thromboembolic events occurring when INRs are outside the therapeutic rangehard clinical
Almost half of all anticoagulant-associated adverse events (hemorrhages and thromboemboli) occur when INRs are outside the therapeutic range, highlighting the critical need for improved anticoagulation control.
Limitations
- Studies may have been missed despite comprehensive search
- One-third of studies did not assign all events to INR ranges
- 28% of studies used previously measured INRs to approximate anticoagulation level at time of events
- Slight variations in target therapeutic range across studies
- Unable to examine differences by anticoagulation indication
- Significant between-study heterogeneity
Cite This Study
Oake et al. (2007) conducted a meta-analysis in Patients taking oral anticoagulants (n=71,065). Oral anticoagulants was evaluated on Proportion of hemorrhages occurring above therapeutic INR range (95% CI 39%-49%). In patients taking oral anticoagulants, 44% of hemorrhages occurred when INRs were above the therapeutic range, and 48% of thromboemboli occurred when INRs were below the therapeutic range.