NICE right to sideline digoxin for atrial fibrillation
By Emma Wilkinson
Digoxin substantially increases the risk of death in patients with atrial fibrillation, and NICE was right when it controversially relegated the drug as a treatment option, researchers conclude.
The increase in deaths came to light by accident in a major trial of antithrombotic therapies, with patients on digoxin at a 58% increased risk of death.
The findings came as a second study found patients in the UK were being inadequately monitored on digoxin, with a quarter having serum levels below the threshold for therapeutic benefit.
An analysis of data from an international trial of more than 7,000 patients – which compared the antithrombolytics warfarin and ximelagatran - found patients on digoxin were dying significantly more often than expected.
The study, published in Heart, also found 8.6% of patients on digoxin suffered strokes, compared with 5.8% of those not on the drug. The researchers admitted that the 53% of patients in the study taking digoxin may have had been at particularly cardiovascular risk, but that the increase in mortality persisted after adjustment.
The team called the finding ‘disturbing' and called for further research in a randomised study.
Lead author Professor Knut Gjesdal, a cardiologist at the University Hospital in Oslo, Norway told Pulse that digoxin might activate blood platelets, which in turn could be a mechanism for increased cardiovascular deaths from thromboembolism and atherothrombosis.
He added: ‘The increased mortality found could be ascribed to digoxin patients being sicker but we tried in vain to validate this explanation by statistical adjustments'
NICE came in for criticism last June when it sidelined digoxin as a first-line treatment for rate control - in favour of beta-blockers or rate-limiting calcium channel blockers - but Professor Gjesdal said this new data supports that move.
The results follow research presented at the annual Drug Utilisation Research Group annual meeting this month which found UK patients with atrial fibrillation taking digoxin in England were being inadequately monitored.
A team at the University of Sunderland found a quarter of patients did not meet the minimum serum digoxin level.
The findings would equate to 52,000 atrial fibrillation patients in the UK missing out on optimum treatment, the researchers warned.
Dr Ahmet Fuat, a cardiology GPSI in Darlington, warned against a knee jerk reaction to the latest research..
‘We shouldn't be saying don't use digoxin. It's an interesting trend but it needs to be ratified in a randomised controlled trial. We have to be very careful about drawing conclusions from post hoc analysis of studies.'Digoxin prescribing in atrial fibrillation Digoxin prescribing in atrial fibrillation
For patients with permanent AF:
Give appropriate thromboprophylaxis
If rate-control is needed use a beta-blocker or rate-limiting calcium antagonist
If further control is needed add in digoxin
Refer if further rate control is needed for other drugs eg amiodarone