Sixty-eight studies using stent insertion and 68 using medical therapy met the inclusion criteria for the review; the proportion of overlap between these studies was unclear. Of the 68 studies using stent insertion, 43 were RCTs; 24 of these scored 3 or more on the Jadad scale. Of the 68 studies using medical therapy, 61 were RCTs; 49 of these scored 3 or more on the Jadad scale. The remaining studies were cohort studies, case-control studies or case series.
Stent insertion (113 treatment arms; 81,807 patients): There were no significant differences between low-dose and high-dose aspirin for major adverse cardiovascular events or for major bleeding at any time point, even when meta-regression was used to adjust for predictive variables.
Medical therapy (111 treatment arms; 207,523 patients): When adjusted for prognostic variables, the incidence of major bleeding was significantly (7 percentage points) higher at one month in those who received a high dose of aspirin. There was no significant difference between low-dose and high-dose aspirin for any other outcome at any time point, even when meta-regression was used to adjust for predictive variables.