Trends Over Time in the Risk of Stroke After an Incident Transient Ischemic Attack

Abstract

Background and Purpose-Long-term population trends in the early risk of stroke after transient ischemic attack (TIA) are unknown. We hypothesized that there has been an appreciable decline in the risk of stroke after TIA for the last decade. Methods-Population-level cohort study from Victoria, Australia (population 5.6 million), using linked data from hospitals, emergency departments, and death records (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011), with a 2-year clearance period to define incident TIAs. Agespecific rates/1000, yearly incident rate ratios, and age-sex-adjusted risk of stroke after TIA were computed. Results-The mean age of 46 971 patients with TIA was 71 (SD=15), 52% women. In patients ≥65 years, annual TIA rates declined between 2001 and 2011 from 5.8 to 4.8/1000 (men) and from 5.3 to 4.2/1000 (women). Yearly incident rate ratios were 0.97 (95% confidence interval, 0.96-0.98) in men and 0.97 (95% confidence interval, 0.97-0.98) in women. Overall, the 90-day stroke risk was 3.1%. Age-sex-adjusted risk of stroke at 90 days after a TIA decreased by 3% per year (odds ratio for the effect of year, 0.97; 95% confidence interval, 0.95-0.99). Male sex, direct discharge from emergency departments, public hospital care, stroke unit care, and absence of vascular risk factors were associated with a downward yearly trend of stroke within 90 days of TIA. Conclusions-Over the last 10 years, there has been a measurable decline in the 90-day risk of stroke after an incident TIA and overall decline in rates of TIA in Victoria, Australia. These trends may reflect improved primary and secondary prevention efforts for the last decade.

Use and Utility of Administrative Health Data for Stroke Research and Surveillance

“…Stroke and transient ischemic attack hospitalization rates using discharge abstract database have been shown to be decreasing. [17][18][19] Although this finding is consistent with the advances in stroke knowledge and care, it is important to recognize that the decreased admissions for transient ischemic attacks may be largely explained by practice variations: more patients with mild or transient symptoms are being evaluated and discharged from the emergency departments without admission. Physicians must recognize that they are active participants in administrative health data generation, and coding is limited by documentation quality.…”

Growth of linked hospital data use in Australia: a systematic review

“…Hospital data linkage to other governmental database (non-hospital) such as Police Road Traffic Accident reports, PBS, MBS, ABS, Child Protection Service records make up 8% of reported data linkage while the remaining 36.2% were from non-specified birth or death records, registries, existing studies or survey populations. Most publications (73%) were descriptive and analytical epidemiological studies, such as those that assessed mortality from rheumatic heart disease on the Aboriginal Australian population, 29 time trends in risk of stroke among elderly Victorians 30 and studies exploring respiratory infection hospitalisations for children. 31 The smallest contributions came from costing studies, economic evaluations, healthcare evaluations and those informing health services planning (12.9%); the rest were validation studies (13.7%).…”

Four-Year Follow-Up of Transient Ischemic Attacks, Strokes, and Mimics

“…10 Several studies have described the prognosis of TIAs and minor strokes. Some are population based, [11][12][13][14] whereas others have reported on patients presenting to hospitals and emergency departments. [15][16][17][18][19] Most outpatient studies were conducted before the establishment of daily rapid access TIA clinics based on the EXPRESS study 6 model.…”

“…Many recent TIA studies have reported 90-day outcomes. 11,20,21 Ten-year results of the OXVASC Study are also available. 22 Up to 60% of patients referred to TIA clinics by nonspecialists turn out to be TIA mimics.…”