Atrial fibrillation – a brave new world?
Today, the National Institute for Clinical Excellence (NICE) made an announcement. Now, that’s not such an uncommon occurrence – they have produced no fewer than 249 ‘technology appraisal guidances’, looking at individual drugs, along with many more clinical guidelines on different aspects of disease.
This one, though, looks at dabigatran, the first new oral anticoagulant agent for nearly 60 years to be approved for the treatment of Atrial Fibrillation, or AF. As our life expectancy increases, more and more people have AF, the most common abnormal heart rhythm. It affects about 1.2 million people in the UK, and about 200,000 people are diagnosed with it every year. People with AF are at least five times more likely to suffer a stroke than the rest of the population – that’s 12,500 strokes every year caused by AF in the UK. Reducing this risk depends on taking medicines to thin the blood.
Until now, the options have been aspirin or warfarin. Aspirin has been around for a long time, and perhaps familiarity has bred contempt. While very effective at reducing the risk of a second heart attack for people who have already suffered one, it reduces the risk of stroke in people with AF by less than 20%. It’s often given instead of warfarin on the assumption that it’s safer, and causes less bleeding – it doesn’t. The risk of bleeding – the major complication of blood-thinning agents – is just as high with aspirin as with warfarin.
Warfarin is extremely effective – it cuts the risk of a stroke in people with AF by almost 2/3. But it is a very tricky drug to get right. Take too much, and you run the risk of catastrophic bleeding. Take too little and you’re not protected against stroke. The dose of warfarin has to be adjusted, sometimes every week, after blood monitoring. Because it interacts with so many medicines and a vast array of foods, some people’s warfarin levels fluctuate wildly, placing them at high risk of complications.
For people like this, dabigatran could be a huge advance. It doesn’t need monitoring or regular dose changes; it doesn’t interact with food; and it’s every bit as effective as warfarin. It’s available in two doses, depending on your age or other complications. In trials, the higher dose was as safe as warfarin and more effective. At the lower dose, it was as effective as warfarin and more safe. It isn’t for everyone – AF is a serious condition with serious complications and it needs serious drugs to deal with it. Like all drugs, dabigatran has side effects and is only approved for people with AF and other risk factors, like high blood pressure, a past stroke or diabetes. If you’re on warfarin and your blood levels and tablets are well controlled, stick with it. If getting your warfarin treatment right is causing problems, this could be a day to remember.