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(Stroke. 2003;34:e166.)
© 2003 American Heart Association, Inc.

Research Reports

Editorial Comment—Antibiotics and Stroke

Anticoagulant Clinic, Sunnybrook & Women’s College Health Sciences Centre, Toronto, Canada

An extract of the first 250 words of the full text is provided, because this article has no abstract.

It is sobering to consider that despite its prevalence and prominence, the cause of atherosclerosis remains unknown. In this issue of Stroke, Brassard et al have addressed its intriguing association with inflammation. If infection plays a role in the genesis of vascular events such as stroke, might antibiotics reduce their incidence?

Briefly, Brassard et al examined retrospectively a large data set of elderly hypertensive patients beginning therapy and, after adjustment for confounders, found that antibiotic use, particularly penicillin, was negatively associated with stroke. They noted a "protective association."

Enthusiasm for a conclusion supporting a popular and intriguing hypothesis should be tempered by consideration of exactly what was done and what was found. Two principles are helpful in assessing the strength of this evidence:

First, in science, an answer cannot be more specific than the question it addresses.

Second, causation cannot be deduced from association.

With regard to the first issue, the hypothesis of the present study was that "subjects treated with antibiotics may be at lower risk of developing clinical manifestations such as cerebrovascular disease." Of the 6 defined antibiotic groups, 3 were associated with fewer strokes, 3 with more. (Patients who had received penicillins, macrolides, and fluoroquinolones experienced somewhat fewer strokes; those receiving tetracyclines, cephalosporins, and other antibiotics experienced somewhat more.) Overall the odds ratio was 0.99 for current use, 0.98 for recent, and 0.99 for past use. Adjustment for confounders resulted in odds ratios of 0.80, 0.81, and 0.87, respectively, and a "statistically significant" negative association for . . . [Full Text of this Article]