Researchers have developed a risk score that could help to identify people at risk of atrial fibrillation in the primary care setting, and may also aid the targeting of prevention measures at high-risk individuals.

Atrial fibrillation is the most common abnormality of heart rhythm that puts people at increased risk of stroke and heart failure.

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 ( Ace ) 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 45-95 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.

Source: The Lancet, 2009

XagenaMedicine_2009