Random-effects risk ratio forest
plot comparing lower-dose aspirin (81 or
160 mg/d) vs placebo. Trial-specifi c risk
ratios are shown as black squares , with
the size of the square being inversely proportional
to the trial-specifi c risk ratio variance.
Horizontal lines represent 95%
confi dence intervals for the trial-specifi c
risk ratios. Pooled risk ratios are shown as
diamonds . The middle of each diamond
corresponds to the risk ratio, and the
width of each diamond represents the
95% confi dence interval. The vertical
dashed lines provide a visual comparison
of the pooled risk ratio with the corresponding
trial-specifi c risk ratios. Tests for
heterogeneity are as follows.