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Long-Term Incidence of Ischemic Stroke Following Transient Ischemic Attack
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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.
abstract
This abstract is available on the publisher's site.
Access this abstract nowBACKGROUND
The short-term incidence of ischemic stroke after a transient ischemic attack (TIA) is high. However, data on the long-term incidence are not well known but are needed to guide preventive strategies.
METHODS
Patients with first-time TIA (index date) in the Danish Stroke Registry (January 2014-December 2020) were included and matched 1:4 with individuals from the background population and 1:1 with patients with a first-time ischemic stroke based on age, sex, and calendar year. The incidences of ischemic stroke and mortality from index date were estimated by Aalen-Johansen and Kaplan-Meier estimators, respectively, and compared between groups using multivariable Cox regression.
RESULTS
We included 21,500 patients with TIA, 86,000 patients from the background population, and 21,500 patients with ischemic stroke (median age 70.8 years [25th-75th percentile 60.8-78.7]: 53% men). Patients with TIA had more comorbidities than the background population, yet less than the control stroke population. The five-year incidence of ischemic stroke following TIA (6.1% [95% CI 5.7-6.5]) was higher than the background population (1.5% [95%CI 1.4-1.6], hazard ratio (HR) 5.14 [95%CI 4.65-5.69 ]), but lower than the control stroke population (8.9% [95%CI 8.4-9.4], HR 0.58 [95%CI 0.53-0.64]). The five-year mortality for patients with TIA (18.6 % [95%CI 17.9-19.3]) was higher than the background population (14.8% [95%CI 14.5-15.1 ], HR 1.26 [95%CI 1.20-1.32 ]), but lower than the control stroke population (30.1% [95% CI 29.3-30.9), HR 0.41 [95%CI 0.39-0.44]).
CONCLUSIONS
Patients with first-time TIA had an ischemic stroke incidence of 6.1% during the 5-year follow-up period. Following adjustment for relevant comorbidities, this incidence was approximately five-fold higher than what was found for controls in the background population, and 40% lower than for patients with recurrent ischemic stroke.
Additional Info
Disclosure statements are available on the authors' profiles:
Long-term Incidence of Ischemic Stroke Following Transient Ischemic Attack: A Nationwide Study During 2014-2020
Circulation 2023 Aug 25;[EPub Ahead of Print], NE Vinding, JH Butt, MD Lauridsen, SL Kristensen, SP Johnsen, J Krøll, PL Graversen, C Kruuse, C Torp-Pedersen, L Køber, EL FosbølFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
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 project,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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