THURSDAY, Nov. 10 (HealthDay News) -- People who have a "mini-stroke" are 20 percent more likely to be dead within nine years than people in the general population, a new study finds.

The risks were most serious for patients older than 65 and for patients with a previous history of stroke and heart problems.

A mini-stroke, or transient ischemic attack (TIA), is a brief interruption of blood flow to part of the brain. Symptoms of mini-strokes may last only a few minutes or a few hours and don't result in long-term disability, but prior research has found that mini-strokes can be warning signs of more serious underlying conditions.

In this study, Australian researchers tracked more than 22,000 adults who were hospitalized with a TIA between July 2000 and June 2007. The patients (median age was 78 for females and 73 for males) were followed for a minimum of two years (median 4.1 years) and their death rates were compared to the general population.

One year after hospitalization, 91.5 percent of the TIA patients were still alive, slightly lower than the 95 percent expected survival in the general population. After five years, about 67 percent of the TIA patients were still alive, compared to an expected 77 percent in the general population. After nine years, the death rate for TIA patients was 20 percent higher than would be expected in the general population.

Older age was associated with an increased risk of death among TIA patients. Compared to patients younger than 50, the risk of death was nearly eight times higher for those aged 75 to 84 and 11 times higher for those 85 and older. The impact of TIA on death rates of people was "minimal."

The study also found that congestive heart failure was associated with a 3.3 times increased risk of death among TIA patients, and atrial fibrillation (abnormal heart rhythm) was linked with twice the risk of dying.

TIA patients who'd previously been hospitalized for stroke were 2.6 times more likely to die than those who didn't have that type of medical history. The effect increased over time and peaked at five times more risk three years after hospital admission for TIA.

The study appears in the journal Stroke.

"People experiencing a TIA won't die from it, but they will have a high risk of early stroke and also an increased risk of future problems that may reduce life expectancy," study author Melina Gattellari, a senior lecturer at the School of Public Health and Community Medicine at the University of New South Wales, Sydney, and Ingham Institute in Liverpool, Australia, said in a journal news release.

"Our findings suggest that patients and doctors should be careful to intensely manage lifestyle and medical risk factors for years after a transient ischemic attack," Gattellari added.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about transient ischemic attack.