Study suggests new risk factor associated with poor stroke outcome

American Heart Association
Friday, 4 July 2003

A buildup of uric acid, a byproduct of protein metabolism, appears to be an independent risk factor for poor outcome after stroke, according to a report in today's rapid access issue of Stroke: Journal of the American Heart Association.

If other studies confirm the findings, steps to lower uric acid may provide a new strategy to improve the prognosis of stroke patients.

Elevated blood urate levels were associated with death or poor neurological status at 90 days in this study. An additional 0.1 millimoles per liter (1.67 milligrams per deciLiter) increase in urate was associated with a 22 percent reduction in the odds of a good outcome, says lead author Christopher J. Weir, Ph.D., of the Acute Stroke Unit of the Division of Cardiovascular and Medical Sciences at the University of Glasgow, Scotland.

The risk of further vascular events also increased with increasing urate levels, he says.

Previous studies have linked elevated uric acid levels to hypertension and coronary heart disease.

Researchers measured urate levels in 2,498 stroke patients within 24 hours of admission and correlated blood urate levels with death or the need for nursing home placement after 90 days.

Weir notes that this is an observational study, so the data cannot be interpreted to mean that high urate causes cerebrovascular events. But he suspects that uric acid promotes the activation of low-density lipoprotein ("bad") cholesterol that could lead to fatty plaque buildup in the arteries. Urate also appears to contribute to the damage caused by reactive oxygen radicals, and it may also promote clotting.

Elevated uric acid can be corrected with gout or hypertension medication. Large-scale clinical trials are needed to confirm whether such treatments are effective in acute stroke.

Co-authors are Scott W. Muir, MBChB, MRCP; Matthew R. Walters, M.D., MRCP; and Kennedy R. Lees, M.D., FRCP.

For more information, or to contact American Heart Association, see their website at: www.americanheart.org