Role of anti-infective strategies in the prevention of stroke.

Case-control studies and a few prospective studies have indicated that chronic infections may add to the risk of stroke and that acute infections may act as trigger factors for stroke. Such chronic infections include periodontal disease, infection with Chlamydia pneumoniae or Helicobacter pylori, and chronic bronchitis. A causal role of these infectious diseases has not been proved, given conflicting study results, possible residual confounding in observational studies, and the lack of evidence from interventional trials. Therefore, special treatment regimens for stroke prevention based on serologic or genomic evidence of infection are not indicated outside of randomized studies at present. However, the preliminary available evidence suggests that in patients with previous cerebral ischemia, clinically diagnosed chronic infections should be taken seriously and should receive the treatment that is indicated according to current guidelines. This may include appropriate treatment of moderate or severe periodontitis and of chronic bronchitis. Inflammatory parameters (eg, C-reactive protein, leukocyte count, fibrinogen) are independently associated with the risk of first or recurrent stroke. The question of whether these indexes are causally related to stroke or merely represent risk markers is not sufficiently clarified. Their use in monitoring individual risk in daily clinical practice is limited at present by the lack of clearly defined therapeutic strategies to modify these parameters, although statins and other drugs can influence inflammatory markers. Observational studies have shown that influenza vaccination is significantly and independently associated with a reduced risk of stroke and myocardial infarction. Although interventional studies in stroke are lacking, it is recommendable that in accordance with current guidelines patients with previous vascular disease, including stroke, patients with high risk of stroke, and all subjects above age 60, receive an influenza vaccination annually.