Table 2.

Observed 15-year absolute risk reductions and numbers needed to treat/harm for aspirin

	Total study population		Women < 65 years		Women ≥ 65 years

	ARR (95% CI)	^aNNT or ^bNNH (95%CI)	ARR (95% CI)	^aNNT or ^bNNH (95%CI)	ARR (95% CI)	^aNNT or ^bNNH (95%CI)

Major cardiovascular event	0.27 (0.06 to 0.86)	371 (116 to >1000)^a	−0.06 (−0.39 to 0.26)	>1000^b (259^b to 382^a)	3.11 (1.67 to 5.27)	32 (19 to 60)^a
Colorectal cancer	0.14 (0.02 to 0.59)	709 (170 to >1000)^a	0.17 (0.04 to 0.55)	581 (181 to >1000)^a	−0.11 (−1.15 to 0.93)	924^b (87^b to 107^a)
Non-colorectal cancer	−0.08 (−0.80 to 0.64)	>1000^b (124^b to 156^a)	−0.32 (−1.06 to 0.42)	312^b (94^b to 237^a)	2.05 (0.43 to 6.28)	49 (16 to 235)^a
Major gastro-intestinal bleeding	−0.75 (−0.50 to −1.00)	133 (100 to 198)^b	−0.64 (−0.40 to −0.87)	157 (114 to 251)^b	−1.66 (−0.50 to −2.82)	60 (35 to 199)^b
Total	−0.42 (−1.29 to 0.45)	238^b (78^b to 223^a)	−0.85 (−1.72 to 0.03)	118^b (58^b to >1000^a)	3.39 (0.98 to 8.42)	29 (12 to 102)^a
Total, adjusted weight of 0.5 for gastro-intestinal bleeding	−0.05 (−0.92 to 0.82)	>1000^b (109^b to 121^a)	−0.53 (−1.40 to 0.34)	189^b (71^b to 291^a)	4.22 (1.59 to 8.90)	24 (11 to 63)^a
Total, adjusted weight of 0.25 for gastro-intestinal bleeding	0.14 (0.00 to 7.59)	703 (13 to >1000)^a	−0.37 (−1.24 to 0.50)	271^b (81^b to 199^a)	4.64 (1.92 to 9.19)	22 (11 to 52)^a
Total, adjusted weight of 0.1 for gastro-intestinal bleeding	0.25 (0.00 to 3.43)	393 (29 to >1000)^a	−0.27 (−1.15 to 0.60)	365^b (87^b to 167^a)	4.89 (2.13 to 9.38)	20 (11 to 47)^a

ARR: Absolute risk reduction (in %); CI: Confidence interval;

NNT: Number needed to treat;

NNH: Number needed to harm.

Risks were estimated based on the cumulative incidence function, accounting for competing risks.