Glossary
After being treated for your first unprovoked blood clot, should you take blood thinners indefinitely or stop?
Research results
Below you will find the results of a group of patients with unprovoked deep vein thrombosis (DVT) or pulmonary embolism (PE) who took blood thinners indefinitely compared to patients who stopped taking blood thinners. The balance between health benefits and drawbacks is a major consideration for a guideline panel to make a recommendation about how long to continue taking blood thinners.
Events per 1000 patients
over 2 years
Outcomes
taking blood thinners indefinitely
Happens to 1000 patients
Stopping blood thinners
Happens to 1000 patients
Certainty of the evidence
PE
24 fewer
9
per 1000
33
per 1000
high
certainty
certainty
DVT
33 fewer
8
per 1000
41
per 1000
high
certainty
certainty
Major bleeding if low risk
11
per 1000
6 fewer
5
per 1000
high
certainty
certainty
Major bleeding if high risk
33
per 1000
18 fewer
15
per 1000
high
certainty
certainty
Death
5 fewer
13
per 1000
18
per 1000
moderate
certainty
certainty
Comparison
Taking blood thinners indefinitely compared to stopping blood thinners
Benefits
In a group of patients with average risk of recurrence, taking blood thinners indefinitely reduces the chance of having a PE - about 24 fewer PE per 1,000 patients. Continuing to take blood thinners indefinitely also reduces the chance of getting DVT - about 33 fewer DVT per 1,000 patients with any blood thinner. If you are taking a DOAC, your chance is about 35 fewer DVT per 1,000 patients. If you are taking LMWH or warfarin, your chance is about 34 fewer DVT per 1,000 patients. If you are taking aspirin, your chance is probably 18 fewer DVT per 1,000 patients.
The chance of dying is probably similar whether you continue to take blood thinners without stopping or do stop taking them.
Drawbacks
If you are at low risk of major bleeding, continuing to take blood thinners indefinitely, rather than stopping medication at 6 to 12 months, increases your chance of having a major bleed - about 6 more bleeds per 1,000 people. If you are at high risk of major bleeding, taking blood thinners indefinitely results in a greater increase in major bleeds – about 18 more bleeds per 1,000 patients.