Within three months after experiencing a transient ischemic attack, commonly known as a mini stroke, more than 14 percent of people suffer a major Stroke , Ohio-based researchers report.

Dr. Dawn Kleindorfer and colleagues at the University of Cincinnati note in the American Heart Association’s journal Stroke that transient ischemic attacks or TIAs are already known to be a strong predictor of subsequent Strokes  and death.

However, the only relatively recent U.S. population-based study of TIAs was conducted in Rochester, Minnesota, they point out. In that city, blacks make up only 1 percent of the population, compared with 13 percent for the United States as a whole.

To gain more representative information on TIAs, the researchers examined data for the 1.3 million inhabitants of the greater Cincinnati and Northern Kentucky areas.

The overall rate of TIAs was 83 per 100,000 population, but blacks and men had significantly higher rates of TIA than did whites and women. The incidence in men was 101.4 per 100,000. Corresponding figures for blacks, whites and women were 98.0, 81.3 and 69.8.

The risk of stroke after TIA was 14.6 percent at 3 months, rising to 17 percent by 6 months. However, the risk of stroke is “extremely high” within 2 days of a TIA, at 6 percent, the researchers add.

Age, race and sex were not associated with the recurrence of TIA or a Stroke , but age was associated with the risk of dying from a stroke.

The researchers “conservatively estimate that about 240,000 TIAs occurred in 2002 in the United States.” They call for further studies of “interventions to prevent ... adverse events after TIA.”

In an accompanying editorial, Dr. S. Claiborne Johnston, UCSF Neurology, San Francisco, agrees and points out that “every stroke after a TIA is a failure.” This may be a failure to use proven therapies, or more frequently, “it is a failure of researchers to establish effective proven therapies for TIA.”

SOURCE: Stroke, April 2005.