Table 3.

Effects of aspirin in primary and secondary prevention trials (meta‐analysis by Antithrombotic Trialists’ Collaboration)1

	Number of events (aspirin vs control)		Rate ratio (95% CI) (aspirin vs control)
	Primary prevention (660 000 person‐years)	Secondary prevention (43 000 person‐years)	Primary Prevention	Secondary prevention
Stroke	655 vs 683	480 vs 580	0.95 (0.85‐1.06)	0.81 (0.71‐0.92)
Ischemic	317 vs 367	140 vs 176	0.86 (0.74‐1.00)	0.78 (0.61‐0.99)
Hemorrhagic	116 vs 89	36 vs 19	1.32 (1.00‐1.75)	1.67 (0.97‐2.90)
Unknown cause	222 vs 226	304 vs 385	0.97 (0.80‐1.18)	0.77 (0.66‐0.91)