Figure 1.
Random-effects risk ratio forest plot comparing any aspirin vs placebo. Trial-specific risk ratios are shown as black squares , with the size of the square being inversely proportional to the trial-specific risk ratio variance. Horizontal lines represent 95% confidence intervals for the trial-specific 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% confidence interval. The vertical dashed lines provide a visual comparison of the pooled risk ratio with the corresponding trial-specific risk ratios. Tests for heterogeneity are as follows. For any adenoma, Q = 5.13 ( P = 0.16) and I 2 = 41.5. For advanced lesion, Q = 1.27 ( P = .74) and I 2 = 0.0. AFPPS = Aspirin/Folate Polyp Prevention Study; APACC = Association pour la Prevention par l’Aspirine du Cancer Colorectal; CALGB = Cancer and Leukemia Group B; CI = confidence interval; ukCAP = United Kingdom Colorectal Adenoma Prevention.