June 8, 2004Neurology
The high risk of stroke immediately after transient ischemic attack
Why the study?
What is the risk of stroke and what are the predictors of stroke following a transient ischemic attack?
Population
2,285 patients diagnosed with transient ischemic attack (TIA) in an emergency room in Alberta, Canada
Design
Cohort
Follow-up
1 year
Authors
Discussion
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Member takes
Implication
Stroke risk after TIA remains high to 1 year; leaves open reliable early prediction by standard factors.
Key Points
- To quantify the short- and long-term risk of stroke following a transient ischemic attack and identify clinical predictors of subsequent stroke.
- Analyzed administrative health records from four provincial databases for the entire population of Alberta, Canada, between April 1999 and March 2000 (N = 2,285 emergency room patients diagnosed with TIA).
- Calculated age-adjusted incidence standardized to the 1996 Canadian population and determined stroke risk starting 24 hours post-presentation using Kaplan-Meier survival curves and Cox proportional hazards modeling.
- The age-adjusted incidence of emergency room-diagnosed TIA was 68.2 per 100,000 population (95% CI, 65.3 to 70.9).
- Cumulative risk of stroke after TIA was 9.5% (95% CI, 8.3 to 10.7) at 90 days and 14.5% (95% CI, 12.8 to 16.2) at 1 year; 1-year combined risk of stroke, myocardial infarction, or death was 21.8% (95% CI, 20.0 to 23.6).
- Hypertension, diabetes mellitus, and older age independently predicted stroke risk at 1 year, but none of these clinical factors reliably predicted early stroke risk.
Structured PICO
What is the risk of stroke and what are the predictors of stroke following a transient ischemic attack?
P
Population
2,285 patients diagnosed with transient ischemic attack (TIA) in an emergency room in Alberta, Canada
O
Outcome
Risk of stroke after TIAhard clinical
The risk of stroke following a TIA is substantial, reaching 14.5% at 1 year, but early risk is not reliably predicted by standard clinical and demographic factors.
Limitations
- Risk assessment began 24 hours after presentation, so the risk of stroke in the first few hours after TIA is not captured
Cite This Study
Hill et al. (2004) studied this question.