Circulation
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- This study investigated the long-term risk of subsequent ischemic stroke in 21,500 patients who experienced a first transient ischemic attack (TIA) compared with that of 86,000 individuals from the general population and 21,500 patients who experienced a first-time ischemic stroke (control group). Over a 5-year follow-up period, the TIA group had a 6.1% incidence of ischemic stroke, which was significantly higher than that in the general population (1.5%) but lower than that in the control stroke group (8.9%). Patients with TIA also exhibited higher mortality rates than the general population but lower rates than the control stroke group.
- These findings underscore the importance of ongoing monitoring and preventive measures following a TIA.
The short-term risk of ischemic stroke following a transient ischemic attack (TIA) is as high as 20% and has been studied extensively. Yet, the long-term risk of stroke remains scarcely described, especially in a contemporary setting and in unselected cohorts. Acute stroke care and treatments, particularly with thrombolysis, have developed significantly, yet the long-term preventive strategies lack evidence. Knowing the long-term risk of stroke is a prerequisite for future randomized clinical trials on various secondary treatment prophylaxis, especially antithrombotic medication.
In a nationwide cohort from the Danish Stroke Registry, we aimed to investigate the 5-year comparative risks of ischemic stroke and all-cause mortality in patients with TIA. Patients with first-time TIA (n = 21,500) were included and matched with the background population (n = 86,000) and a control stroke population (n = 21,500). The median age was 71 years and 53% were male in the three matched study groups. The crude cumulative incidence of ischemic stroke was 6.1% (95% CI, 5.7–6.5), significantly higher than that in the background population ([1.5%; 95% CI, 1.4–1.6; P < .01]; [aHR, 5.14; 95% CI, 4.65–5.69]), yet lower than that in the control stroke population ([8.9%; 95% CI, 8.4–9.4; P < .01]; [aHR, 0.58; 95% CI, 0.53–0.64]). Importantly, these differences persisted beyond the first 90 days. The same result was observed for the outcome of mortality; however, patients with TIA had a 60% lower rate of mortality than the control stroke population. This highlights that, by preventing a stroke among patients with TIA, we may also prevent excess mortality.1
This study along with two other studies, the Framingham Heart Study2 and the TIAregistry.org,3 provide consistent results on three different populations; stroke risk continues to rise beyond the first high-risk period. A window of opportunity exists to reduce stroke risk among patients with TIA. Special attention to cardiovascular risk factors is needed in the long term after TIA, and further research on preventive measures is paramount.
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