That finding, reported in the February issue of Stroke, comes from a substudy of patients enrolled in a multinational trial investigating the prevention of recurrent stroke.
Dr. Hans Christoph Diener, at the University Duisburg-Essen, Germany, and colleagues explain that 1041 of the more than 20,000 participants in the PRoFESS trial underwent imaging studies. MRI detected silent brain infarction in 207 of them, and this group was matched by age and sex to the same number without SBI.
During a mean follow-up of 2.5 years, second strokes occurred in 27 patients with SBI and 19 in the non-SBI group. While the recurrence rates of 13.0% and 9.2% translated to an odds ratio of 1.42, the difference was not statistically significant (p=0.24), the authors report.
Secondary outcomes were also not significantly different between the two groups. A combined vascular endpoint of stroke, myocardial infarction and vascular death occurred in 33 (15.9%) patients with SBI and 24 (11.6%) in the matched group (OR 1.38; p=0.24), and mortality rates were 6.8% versus 2.9% (OR 2.33; p=0.08), according to the report.
The prevalence of SBI was lower than expected in the study, which Dr. Diener and colleagues attribute to the relatively young mean age (66 years) of the patients. This may explain the lack of statistically significant difference between the endpoints, they suggest.
That said, they conclude, “The presence of SBI in patients with recent mild noncardioembolic ischemic stroke could not be shown to be an independent risk factor for recurrent stroke, other vascular events, or a higher mortality.”