Five RCTs were included (1,092 patients were randomised but only 699 patients were included in the analysis).
Three studies excluded patients after they had started the study medication. The first RCT excluded patients from the analysis who did not meet the protocol or who had adverse events; the second RCT excluded patient who did not receive surgery, declined to participate, or had poor outcome; the third RCT excluded patients whose aneurysm could not be found or clipped during surgery.
Poor outcome (5 RCTs, 671 patients): the meta-analysis showed no significant difference between antiplatelet therapy and placebo for poor outcome; the RR was 0.87 (95% CI: 0.65, 1.17). No significant statistical heterogeneity was detected (P=0.82). Similar results were found for studies of aspirin (RR 0.78, 95% CI: 0.35, 1.74) and for studies starting treatment pre- or post-operatively (the results were reported).
Delayed cerebral ischaemia (3 RCTs, 258 patients): the meta-analysis showed that antiplatelet therapy significantly reduced DCI compared with placebo; the RR was 0.65 (95% CI: 0.47, 0.89). No significant statistical heterogeneity was detected (P=0.65). The NNT was 7 (95% CI: 4, 40). The results for subgroups were not reported.
Intracranial haemorrhage (4 RCTs, 678 patients): the meta-analysis showed no significant difference between antiplatelet therapy and placebo; the RR was 1.19 (95% CI: 0.76, 1.85). The NNH was 500 (95% CI: 21, infinity). Similar results were found for studies starting treatment post-operatively (the results were reported).