Date: 09 July 2018
Research funded by the NIHR has found that new drugs used to treat serious blood clots are associated with a lower risk of major bleeding than the older anti-clotting drug warfarin.
The findings provide initial reassurance about the safety of direct oral anticoagulants (DOACs) as an alternative to warfarin for all new patients.
Anticoagulants are used to prevent and treat potentially dangerous blood clots (venous thromboembolism) and reduce the risk of stroke in patients with atrial fibrillation or who have had acute pulmonary embolism, deep vein thrombosis, or hip or knee replacement surgery.
Warfarin has been the main treatment for venous thromboembolism, but regular checks are required to ensure the drug is at the right level in the bloodstream. DOACs are increasingly being used as an alternative because patients don’t need regular tests.
This study, funded by the NIHR School for Primary Care Research, compared health outcomes of 196,000 patients treated with commonly prescribed DOACs - apixaban, rivaroxaban or dabigatran - or warfarin over a five-year period.
The researchers at the University of Nottingham looked at two groups of patients - people taking anticoagulants to treat atrial fibrillation and those taking anticoagulants for other medical conditions.
In both sets of patients apixaban was found to be the safest drug, with lower risks of major bleeds and of intracranial and gastrointestinal bleeding than with warfarin. In the group with atrial fibrillation, dabigatran was linked to a reduced risk of intracranial bleed, while rivaroxaban was linked to a reduced risk in the group with other conditions.
Rivaroxaban and low dose apixaban were, however, associated with increased risks of all-cause mortality compared with warfarin in both groups of patients, the researchers report in their BMJ paper.
Lead author of the study, Dr Yana Vinogradova, said: “Extending understanding of the effects and risks of these drugs to the group of patients who have other conditions requiring anticoagulation but normal heart beat will be helpful for patients and clinicians.
“The results of this large new study are important because previous research using randomised controlled trials has only included carefully selected patients who are closely monitored. Other observational studies have in most cases concentrated solely on patients with atrial fibrillation, so until now there has been no overall picture of information for use of anticoagulants in other patients.”
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