Stroke prevention in the elderly may need to focus on the concomitant effects of multiple risk factors rather than on a specific risk factor such as atrial fibrillation (AFib), according to research presented Aug. 30 at ESC Congress 2015 in London.

Researchers investigated incident ischemic stroke rates in relation to age and increasing cardiovascular risk factors (vascular disease, hypertension, diabetes or heart failure), and the incremental impact of AFib on these stroke rates. The study population was a random sample of 425,600 patients without prior ischemic stroke from a Chinese medical insurance dataset of more than 10 million patients from 2001 to 2012. The rate of ischemic stroke was calculated in patients with and without AFib in relation to age groups (<65, 65-74, ≥75 years old) and increasing risk factors using the CHA₂DS₂-VASc score.

Overall, ischemic stroke incidence (per 100 person-years) was 0.35 (95 percent confidence interval [CI] = 0.34-0.35) in the non-AFib population and 1.11 (95 percent CI = 0.84-1.45) in patients with AFib (p<0.001). With increasing CHA₂DS₂-VASc scores, ischemic stroke incidence per 100 person-years increased in both non-AFib and AFib populations (both p value for trend, < 0.001). The relative risk ratio of ischemic stroke in the population with CHA₂DS₂-VASc score ≥2 was more than doubled compared to those with CHA₂DS₂-VASc score ≤1. However, for patients aged ≥75, there was no significant difference in mean CHA₂DS₂-VASc score between the non-AFib and AFib population (p=0.086). Investigators also noted that the non-AFib population with ≥2 additional comorbidities had an increased stroke incidence with age (p value for trend, <0.001), while the non-AFib population aged ≥75 years with ≥2 additional comorbidities had the highest risk for the incident stroke (5.6 percent), similar to the AFib population with a CHA₂DS₂-VASc score of 5 (4.2 percent).

"The non-AFib elderly population (age ≥75 years) had comparable CHA₂DS₂-VASc scores to the AFib population, but a numerically higher stroke incidence," said principal investigator Yutao Guo, MD, from the PLA General Hospital in Beijing, China. "Non-AFib patients with multiple additional comorbidities also had high ischemic stroke rates, especially in the elderly, with the stroke incidence similar to an AFib population with CHA₂DS₂-VASc >4."

According to Guo, a more holistic approach to stroke prevention is required and current prevention strategies need to adapt to changing risk profiles. "It will be important to identify risk factors as they emerge and find ways of identifying those at high risk to prevent developing incident stokes in the ‘general’ population," she said.

Keywords: Asian Continental Ancestry Group, Atrial Fibrillation, Risk, Risk Factors, Stroke, ESC Congress

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