Risk of First Stroke Rises With Risk-Factors

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Risk of First Stroke Rises With Risk-Factor Prevalence

As the number of ischemic-stroke risk factors goes up in persons without a history of stroke or atrial fibrillation (AF), so does the risk of stroke–so much so that with at least three risk factors, the stroke risk rises to rival that in patients with AF, suggests an analysis of more than four million persons in health care registries across Denmark [1].

“This has not been shown before in patients without prior stroke or AF,” Dr Christine Benn Christiansen (Gentofte Hospital, Copenhagen, Denmark) told heartwire . “If you have multiple risk factors, you can still have a high risk of stroke, even without atrial fibrillation.” The risk factors in the analysis included MI, heart failure, diabetes, hypertension, and advanced age, among others.

Dr. Lane: what this study says is that while Atrial Fibrillation have a higher risk of stroke than the general population, having other risk factors equals the danger of having AF.  These factors are: myocardial infarction (heart attack), diabetes, hypertension (high blood pressure), and just being older.

In the analysis, a presence of at least five such risk factors was associated with an ischemic stroke rate of 7.27 per 100 person-years without prevalent or incident AF and 8.0 per 100 person-years with prevalent or incident AF.

The gulf between the two stroke rates was pronounced in persons without any of the stroke risk factors and then progressively diminished among those with one to two and three to four risk factors, until at five or more risk factors there was “hardly any difference” in stroke risk between persons with vs without prevalent or incident AF, she said.

Benn Christiansen presented the analysis today at a briefing for reporters here at the European Society of Cardiology (ESC) 2013 Congress. It encompassed 4 037 576 adults without existing or incident AF over a 10-year period starting in 2000, 31 716 with AF at baseline, and 131 153 with AF developing during follow-up.

Rate of Stroke Per 100 Person-Years by Number of Risk Factors in Cohort Without AF vs Cohort With AF at Baseline or During Follow-Up

Number of risk factors* No AF, n=4 037 576 Prevalent or incident AF, n=161 869
0 0.32 2.55
1–2 1.77 5.69
3–4 4.88 6.96
>5 7.27 8.00

*Risk factors=MI, peripheral artery disease, arterial embolism, excessive alcohol consumption, heart failure, carotid stenosis, retinal occlusion, chronic systemic inflammation, chronic kidney disease, venous thromboembolism, epilepsy, migraine, diabetes mellitus, hypertension, and age >75 years

According to Prof Hans-Christoph Diener (University Hospital Essen, Germany), present at the briefing as a spokesperson for the ESC, the findings “have practical consequences” because preventive therapy for persons without a history but moderate to high risk for AF or stroke is understudied.

He pointed to the Aspirin to Reduce Risk of Initial Vascular Events (ARRIVE) trial, which is randomizing about 12 000 patients in seven countries in Europe and North America to daily aspirin vs placebo; the patients have two to four cardiovascular risk factors and no history of CV events or procedures. It’s following the groups for five years for the primary end point of first nonfatal MI or nonfatal stroke or CVD death, including MI and stroke death.

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