How Does Number of Risk Factors Affect Prognosis in Young Patients With Ischemic Stroke?

Background and Purpose-We aimed to explore clinical features of young patients with ischemic stroke with no traditional vascular risk factors and to assess the impact of risk factor counts on outcomes. Methods-We included 990 patients aged 15 to 49 years with first-ever ischemic stroke followed for a mean of 9.0 +/- 3.8 years (survivors). Risk factors were categorized as well-documented and less well-documented. Outcome measures were unfavorable functional outcome (3-month modified Rankin Scale 2-6); recurrent ischemic stroke; myocardial infarction or other arterial noncerebrovascular event; and death from any cause. Results-Compared with those with at least 1 well-documented risk factor, the 127 (12.8%) patients without risk factors were younger (median age, 37 versus 44 years; P<0.001), likely to be females (54.3% versus 34.9%; P<0.001), and they had more frequently a low-risk source of cardioembolism (21.3% versus 8.1%; P<0.001), internal carotid artery dissection (12.6% versus 6.4%; P=0.011), or vertebral artery dissection (17.3% versus 7.2%; P<0.001). The groups had similar 3-month functional outcomes. Patients without well-documented risk factors had less frequently recurrent ischemic strokes (4.7% versus 13.6%; log rank P=0.014), noncerebrovascular arterial events (0% versus 6.1%; P=0.008), and lower long-term mortality (3.4% versus 14.3%; P=0.003) than did those with at least 1 risk factor. Adjusted for demographics and stroke etiology, the number of well-documented risk factors was associated with higher risk for noncerebrovascular events. Increasing count of less well-documented risk factors was, in turn, independently associated with higher long-term mortality. Conclusions-In young adults with first-ever ischemic stroke, risk factor counts added independent prognostic information regarding noncerebrovascular events and mortality. (Stroke. 2012;43:356-361.)