Study designs of evaluations included in the review
Randomised controlled trials (RCTs) which tested aspirin in addition to oral anticoagulation with vitamin K antagonists were included. Clinical trials in which the target intensity of anticoagulation was different between the aspirin/no aspirin arms were excluded.
Specific interventions included in the review
Daily aspirin in combination with warfarin was compared to warfarin alone or to warfarin plus dipyridamole. Dose of aspirin ranged from 75 mg to 1,000 mg daily. The Mean International Normalized Ratio (INR) was assessed using prothrombin times or thrombotest and levels ranged from 1.1 to 5 across studies.
Participants included in the review
Participants included patients with prosthetics valves or atrial fibrillation and men with coronary risk factors.
Outcomes assessed in the review
Frequency of intracranial haemorrhage (ICH), including intraparenchymal, subdural and epidural, was assessed. Methods of diagnosis of ICH included unspecified clinical criteria. Primary sub-arachnoid haemorrhage was excluded.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.