Antithrombotic prevention in vascular disease: bases for a new strategy in antithrombotic therapy

Table 2 Comparison of ischemic risk prevention and bleeding with clopidogrel plus aspirin (clop + ASA) versus aspirin plus placebo (ASA + placebo).

	Ischemic Events				Bleeding Events
Trial (observation period)	clop + ASA (%)	ASA + placebo (%)	p	NNT	clop + ASA (%)	ASA + placebo (%)	p	NNH
Cure [36] (1 year)	9.3	11.4	<0.001	47.6	major 3.7 minor 5.1 total 8.5	major 2.7 minor 2.4 total 5.0	<0.001 <0.001 <0.001	100 37 28.6
Credo [38] (1 years)	8.5	11.2	0.02	37.0	severe 8.8 minor 5.3	severe 6.7 minor 5.6	0.07 0.92	250
Charisma [3] (2.5 years)	6.8	7.3	0.22	200	severe 1.7 moderate 2.1 moderate + severe 3.8	severe1.3 moderate 1.3 moderate + severe 2.6	0.09 <0.001 <0.001	250 125 83.3

Comparison of ischemic risk prevention and bleeding with clopidogrel plus aspirin (clop + ASA) versus aspirin plus placebo (ASA + placebo). Aspirin plus clopidogrel increased the incidence of bleeding events compared with aspirin plus placebo. Comparing the primary endpoint reduction with the two treatments, it appears that increased frequency of bleeding can limit the benefits of combined therapy.
NNT: Number Needed to Treat
NNH: Number Needed to Harm