Seven RCTs with 3,402 participants were included (3,382 participants included in the analyses).
Across all studies, clopidogrel and ticlopidine groups did not differ significantly for the composite primary outcome (pooled OR 0.90, 95% CI: 0.44, 1.84, p=0.77). Significant heterogeneity was present (I-squared 58.5%; p=0.02). The studies in which clopidogrel loading was used (based on six RCTs) showed a significant advantage of clopidogrel (pooled OR 0.60, 95% CI: 0.36, 0.99, p=0.05), without significant statistical heterogeneity. The two comparisons in which clopidogrel was not front-loaded showed a significant advantage of ticlopidine (pooled OR 2.31, 95% CI: 1.33, 4.0, p=0.003); again, statistical heterogeneity was not significant. The results for death and MI separately were similar to those for the primary outcome.
There were no significant differences between clopidogrel and ticlopidine for target vessel revascularisation or blood dyscrasia.
Meta-regression analysis found a significant interaction between loading dose of clopidogrel and its effectiveness relative to ticlopidine (p=0.012).
There was no evidence of publication bias from the funnel plot or statistical tests.