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Nine years after discharge, the survival of patients hospitalized with a transient ischemic attack (TIA) was 20% lower than expected in the general population, according to an Australian study.

Before a decade had passed, 50% of TIA patients had died; the mortality rate was minimal among patients younger than 50, but significant among those older than 65, Melina Gattellari, PhD, of the University of New South Wales, and colleagues reported online in Stroke.

There is a lack of modern data quantifying the effect of TIA on survival, and recent data do not take into account expected survival, they wrote.

The findings emerged from a study of 22,157 adults hospitalized with a TIA from July 2000 through June 2007 in New South Wales, Australia. Using data from the PRISM (Program of Research Informing Stroke Management) study, the investigators estimated survival relative to the age- and sex-matched general population.

The study extended up to nine years after hospitalization for TIA, comparing the relative risk of excess death between selected subgroups.

At one year, 91.5% of patients were alive compared with 95% expected survival in the general population.

After five years, 67.2% were still alive compared with an expected survival of 77.4%, a relative survival ratio of 86.8%. A TIA diagnosis resulted in a 13.2% relative decrease in five-year survival.

Compared with the general population, men had a significantly lower relative survival in the first year, but not in subsequent years.

At one year, women had a significant 21% lower risk of death compared with men (relative risk 0.79, 95% CI 0.69 to 0.90, P<0.001), but that survival difference was not significant after one year.

Relative survival decreased with increasing age. Compared with patients younger than 50, those 50 to 64 were 1.82 (CI 1.14 to 2.87 ) times more likely to die. Those 65 to 74 were 4.74 times (CI 3.07 to 7.30) more likely.

For those ages 74 to 84 and 85-plus years, the relative risk of death was almost eight (7.77) and 11 (11.02) times higher respectively.

Of all the risk factors assessed, congestive heart failure, atrial fibrillation, and prior hospitalization for stroke had the greatest negative effect on survival.

The sex advantage for women in the year after a TIA might be explained by improved risk management for women in that first year although data are lacking, the researchers said.

Another possibility is that women might be more likely to have had benign conditions misclassified as a TIA, they added.

Study limitations included misclassification problems. Because there is no gold standard diagnostic test for TIA, uncertainty about the diagnosis and its neurovascular significance is a problem in all TIA studies, the researchers said.

In addition, these results cannot be generalized to people who do not present to a hospital for medical care but rather to a healthcare physician or who were discharged from an emergency department. Hospitalized patients are managed differently from those in an emergency department.

Comparing observed and expected survival rates establishes the true effect of TIA on mortality and should inform healthcare services planning, secondary prevention, and follow-up strategies, Gattellari said.

Patients and physicians are advised to carefully manage lifestyle and medical risk factors for years after a TIA.

From the American Heart Association:

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