Scientists have developed a risk score that could help to identify people at risk of atrial fibrillation (the most common abnormality of heart rhythm that puts people at increased risk of stroke and heart failure) in the primary care setting, and may also aid the targeting of prevention measures at high-risk individuals. These are the findings of an Article to be published in this week's edition of The Lancet.
One in four people will develop atrial fibrillation in their lifetime. But prevalence is expected to rise substantially over the next few decades because of the aging population and increased survival of people with heart disease, which could result in 15.9 million cases of atrial fibrillation by 2050 in the US alone.
A variety of therapies have been shown to offer protection against the onset of atrial fibrillation including statins, fish oil, and angiotensin-converting enzyme inhibitors. In addition, previous studies have identified the common risk factors that predispose people to atrial fibrillation, such as ageing, diabetes, hypertension, obesity, and cardiovascular disease. But to date, no tool has been devised that combines multiple risk factors to calculate an individual's absolute risk.
Therefore, Renate Schnabel from the Johannes Gutenberg-University in Mainz, Germany, and Emelia Benjamin from Boston University School of Medicine in Massachusetts, USA, and colleagues, aimed to create a new way to score an individual's risk using clinical characteristics that can be easily assessed in primary care settings.
Using data from the Framingham Heart Study, they selected 4764 individuals aged 45 years who did not have atrial fibrillation, from 80 444 examinations done between June, 1968, and September, 1987. Participants were followed over 10 years and monitored for atrial fibrillation, to develop a risk score from clinical characteristics, examination, and echocardiographic measures. Multivariable Cox regression models were used to assess risk factors associated with the development of the condition.
Findings showed that 457 (10%) of the participants developed atrial fibrillation over the 10 years. Age, sex, body-mass index, systolic blood pressure, treatment for hypertension, PR interval, clinically significant heart murmur, and heart failure were the strongest risk factors associated with atrial fibrillation, and were included in the final model. The researchers developed a scoring system for each of these risk factors and assigned the total score to an absolute risk of developing atrial fibrillation over 10 years.
The risk score was shown to have good predictive value and had similar accuracy in both young and old individuals. The score was only slightly improved by the inclusion of standard echocardiographic measures.
The risk of atrial fibrillation in 10 years was shown to vary with age—53 (1%) participants younger than 65 years had more than 15% risk, compared with 783 (27%) older than 65 years.
The authors conclude: "Our risk prediction score provides clinicians with an easily applicable method to improve risk assessment and communication of risk for individuals, and targeting intervention in routine clinical practice."
In an accompanying Comment, David Brieger and Ben Freedman from Concord Hospital, University of Sydney in Australia, say: "Atrial fibrillation is the most common sustained arrhythmia, and is associated with a doubling of the... mortality rate...particularly within the first 4 months of diagnosis...With this condition, few would argue against the assertion that an ounce of prevention is worth a pound of cure. This predictive model is the first step in that direction."
They conclude that identification of a group at increased risk of development of atrial fibrillation would make it possible to test new or currently available therapies which might prevent this arrhythmia.
Professor Emelia Benjamin, Boston University School of Medicine, Massachusetts, USA. T) +1 617 823 4418 E) emelia@bu.edu
Professor Ben Freedman, Concord Hospital, University of Sydney, Sydney, Australia. T) +61 411 591 633 (mobile) E) ben@med.usyd.edu.au (Please note, Sydney is 11 hours ahead of the UK)
Associate Professor David Brieger, Concord Hospital, University of Sydney, Sydney, Australia. T) +61 417 689 676 (mobile) E) briegster@gmail.com (Please note, Sydney is 11 hours ahead of the UK)
For full Article and Comment see: http://press.thelancet.com/atrialfibrillation.pdf
Journal
The Lancet