Most AF patients benefit from oral anticoagulation
MedWire News: Almost all patients with atrial fibrillation (AF) should receive oral anticoagulation to prevent stroke, say researchers.
"When managing patients with AF, we essentially need to ask the question 'who are the patients with bleeding risks that exceed the risk of ischaemic stroke?' " say Leif Friberg (Karolinska Institute, Stockholm, Sweden) and co-workers.
In the current study, involving over 170,000 AF patients indentified in the Swedish Hospital Discharge Register, just 0.4% of patients fell into this category.
"Patients where bleeding risks far exceed the risk for ischaemic stroke are likely to be found among patients with malignant hypertension, ongoing occult gastrointestinal bleeds or patients with recurrent spontaneous ICH (eg, cerebral amyloid angiopathy)," the team notes in Circulation.
Overall, during an average 1.5 years of follow up, 9296 patients had an ischemic stroke, 13,281 had any thromboembolic event, 1600 had an intracerebral hemorrhage (ICH), and 5810 had a major bleed.
Other patients unlikely to benefit from anticoagulation were those who had a moderate or low bleeding risk based on HAS-BLED scores and a CHA2DS2-VASc risk score of 0. In other words, patients who were younger than 65 years, male, and did not have heart failure, diabetes, previous stroke, or any form of vascular disease and had only one or two bleeding risk factors. This group had a slight negative net clinical benefit, of a 1.7% increase in the annual event rate.
All other patients gained net clinical benefit from oral anticoagulation therapy, even with ICH weighted at 1.5 times worse than ischemic stroke. In general, patients with high scores in both categories gained the most benefit, with the largest gain, of a 6.3% annual reduction, seen in patients with a HAS-BLED score of 4 and a CHA2DS2-VASc score of 6.
The researchers note that the CHADS2 score was unable to identify the small subset of patients who had no, or a negative, benefit from anticoagulation.
In an accompanying editorial, Valentin Fuster and Jason Chinitz (Mount Sinai School of Medicine, New York, USA) say that the researchers' proposed approach to anticoagulation "will make clinical decisions frequently less complex, and will undoubtedly result in many more patients with AF being offered antithrombotic therapy than are currently in the US."
They also point out that "a low-risk CHADS2 score may provide false reassurance, prompting clinicians to defer anticoagulation in patients who might actually benefit."
And they add: "Future assessments of net benefit using novel agents may progressively favor treatment in patients at incrementally lower risk of stroke, so that even more patients with AF will be offered antithrombotic therapy."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Eleanor McDermid