CRD Summary: This review found that aspirin treatment in patients with peripheral artery disease provided a statistically significant reduction in nonfatal stroke but not in cardiovascular events. The authors also concluded that given the limited statistical power of their analysis, further randomised controlled trials are required. These cautious conclusions are likely to be reliable.

[Included studies used aspirin monotherapy or aspirin combined with dipyridamole. ]

CRD Commentary: The review question and the inclusion criteria were clear. The authors searched a number of relevant databases and made systematic attempts to identify unpublished studies. This reduced the chances of relevant studies being omitted from the review and reduced the chances of publication bias. Publication bias was assessed and no evidence for it found. The authors reported using methods designed to reduce reviewer bias and error in the selection of studies, but not in the extraction of data and the assessment of validity. A validity assessment was conducted using an appropriate tool and was used to inform the synthesis. Despite clinical heterogeneity, the decision to use meta-analysis appeared appropriate. The cautious conclusions accurately reflected the results of the review and are likely to be reliable.