Dabigatran, rivaroxaban and warfarin are similarly effective for stroke prevention in patients with atrial fibrillation (AF) and multiple chronic conditions.
The findings, from a retrospective US study of Medicare data, extend the evidence for oral anticoagulants in a higher risk group than is typically represented in randomised controlled trials.
The study comprised almost 147,000 patients over 65 years initiating on one of the NOACs or warfarin within 90 days of an AF diagnosis. More than 75% of patients had a moderate to high CHA2DS2-VASc (>4) and more than 32% had a score higher than 6.
The study found lower rates of major haemorrhage in dabigatran users compared to rivaroxaban users in patients with a moderate to high burden of chronic conditions.
And rates of gastrointestinal haemorrhage were lower with dabigatran or warfarin compared to rivaroxaban users.
Mortality rates were generally lower in both rivaroxaban and dabigatran users compared with warfarin users in all subgroups of patients based on their burden of comorbidities.
The study authors said the choice of anticoagulant in patients with multiple conditions was complex.
“Recent data suggest that physicians are more likely to prescribe [NOACs] to healthier patients with fewer comorbidities, while higher CHA2DS2-VASc and HAS-BLED scores are associated with lower probability of [NOAC] prescription compared with warfarin.”
“Our findings of similar effectiveness of all three anticoagulants for stroke prevention are assuring and will lend confidence to clinicians regarding [NOACs] use even in complex patients,” it said.
“It is reassuring to note the decreased mortality risk associated with [NOACs] use in these high-risk patients compared with warfarin use which may motivate clinicians to prescribe [NOACs] in patients with complex illness.”
Australian AF guidelines recommend an integrated management approach, including input from a multidisciplinary care team, in older and more complex patients.
“The combination of impaired hepatic, renal, cognitive function, high risk medications and poly-pharmacy make drug interactions and complications more likely,” the guidelines said.
“More research needs to be carried out to arrive at definite conclusions about preference of one NOAC over the other in this patient population.”
The findings are published in JAMA Network Open.