Studies had suggested anticoagulation may increase the health risks in these patients, while others found no added risk.
But researchers in Sweden have taken a step closer to clarifying appropriate treatment, after their study found a lower risk of thrombotic events and death, with no extra risk of bleeding on warfarin.
A team from Karolinska Institutet in Stockholm looked at data on 24,317 patients, all of whom had AF and prior MI.
Around 52% had CKD stage three or higher based on eGFR measurements. A fifth of patients (22%) were prescribed warfarin at discharge after their MI.
Patients on warfarin had a lower one-year risk of death, MI and stroke, compared with patients not on warfarin. There was no added risk of bleeding.
Importantly, this reduced risk was seen regardless of the severity of CKD. Risks were reduced by 25% in those with stage 3 CKD, and up to 45% among stage 4-5 disease.
There was also no added risk of bleeding at any severity of CKD among patients on warfarin.
Nonetheless, rates of stroke, MI and death increased with worsening of CKD severity, as did bleeding events, for all patients.
Authors concluded: ‘Warfarin treatment was associated with a lower one-year risk of the composite outcome of death, MI and ischaemic stroke, without a higher risk of bleeding, in consecutive patients with acute MI and AF. This association was not related to the severity of concurrent CKD.’
In an accompanying editorial, Dr Wolfgang Winkelmayer and Dr Mintu Turakhia of the Stanford University School of Medicine in California said the study ‘provides the best evidence to date that vitamin K antagonists are associated with improved clinical outcomes and no significant increased risk of bleeding in patients with MI and AF with advanced CKD.’