Table 4.

Estimated number-needed to treat to prevent a CHD or CVD event and number-needed to harm to cause a major bleed with aspirin in men and women in MESA stratified by qualification for aspirin by AHA guidelines and CAC.

Men
10-year CHD risk < 10%	No. of participants	5-yr CHD event rate	Relative CHD risk reduction with ASA	Estimated5-yr NNT	5-yr estimated absolute increase in bleeding rate	Estimated5-yr NNH
CAC = 0	461	0.23%		1389	0.26%	388
CAC 1–99	178	1.74%	32%	180
CAC ≥ 100	71	5.68%		56
10-year CHD risk ≥ 10%	No. of participants	5-yr CHD event rate	Relative CHD risk reduction with ASA	Estimated5-yr NNT	5-yr estimated absolute increase in bleeding rate	Estimated5-yr NNH
CAC = 0	373	0.55%		571	0.26%	388
CAC 1–99	386	3.72%	32%	85
CAC ≥ 100	392	6.42%		49

Women
Global CVD Risk < 10%	No. of participants	5-yr CVD event rate	Relative CVD risk reduction with ASA	Estimated 5-yr NNT	5-yr estimated absolute increase in major bleeding	Estimated5-yr NNH
CAC = 0	1167	0.45%		1322	0.20%	512
CAC 1–99	299	1.37%	17%	430
CAC ≥ 100	107	4.84%		122
Global CVD Risk ≥ 10%	No. of participants	5-yr CVD event rate	Relative CVD risk reduction with ASA	Estimated 5-yr NNT	5-yr estimated absolute increase in major bleeding	Estimated5-yr NNH
CAC = 0	360	2.33%		253	0.20%	512
CAC 1–99	230	4.95%	17%	119
CAC ≥ 100	205	4.68%		126

Abbreviations: CHD Coronary Heart Disease, CVD – Cardiovascular Disease, CAC – Coronary Artery Calcification, MESA – Multi-Ethnic Study of Atherosclerosis, NNT – Number needed to treat, NNH – number needed to harm