UK doctors still undertreating major risk factor for stroke

Despite significant improvements in stroke prevention over the past decade, and a fall in incidence and deaths, UK doctors are still undertreating one of the major risk factors - atrial fibrillation - reveals research published in BMJ Open.

Atrial fibrillation, or AF for short, describes abnormal heart rhythms. Its treatment has been prioritised in the NHS in a bid to cut preventable deaths and disability from stroke.

The researchers base their findings on an analysis of stroke data drawn from the General Practice Research Database (GPRD) for the period 1999 to 2008. The GPRD contains long term anonymised data on three million UK primary care patients.

More than 32,000 adults had a stroke, one in seven (15%) of which were fatal, during the study period.

Women were more likely to die of a stroke than men, even after taking account of age. The average age for a first stroke was 77 years for women and 71 years for men.

The figures showed significant improvements both in the number of new cases of stroke and in subsequent survival.

The prevalence of stroke rose by 12.5%, but the number of new cases fell by almost a third (30%) over the decade - from 1.48 per 1,000 person years in 1999 to 1.04 in 2008.

Risk Factors for Ischemic Stroke Age, gender, race, ethnicity, and heredity have been identified as markers of risk for stroke. Although these factors cannot be modified, their presence helps identify those at greatest risk, enabling vigorous treatment of those risk factors that can be modifed.

Age is the single most important risk factor for stroke. For each successive 10 years after age 55, the stroke rate more than doubles in both men and women. Stroke incidence rates are 1.25 times greater in men, but because women tend to live longer than men, more women than men die of stroke each year.

An increased incidence of stroke in families has long been noted. Potential reasons are a genetic tendency for stroke, a genetic determination of other stroke risk factors, and a common familial exposure to environmental or lifestyle risks. Earlier studies suggested an increased risk for men whose mothers died of stroke and women who had a family history of stroke. In the Framingham Study an offspring analysis revealed that both paternal and maternal histories were associated with an increased risk of stroke.

Among those aged 80 and over, who are at the highest risk of stroke, the fall was even greater, at 42%.

The rate of deaths within 56 days of a first stroke almost halved, falling from one in five (21%) in 1999 to nearly one in 10 (12%) in 2008.

It has long been known that patients who have chronic, persistent, or frequent episodes of atrial fibrillation have an increased risk of stroke.

The increased risk comes from the fact that, during atrial fibrillation, the heart's atria are not squeezing effectively. Consequently, the blood tends to "pool" in the atria - and whenever blood flow is disrupted, blood clotting can occur. Clots that form in the atria can break loose eventually, and if the clots travel through the arteries to the brain, a stroke results.