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. Author manuscript; available in PMC: 2010 Mar 1.
Published in final edited form as: Ann Intern Med. 2009 Sep 1;151(5):297–305. doi: 10.7326/0003-4819-151-5-200909010-00003

Table 3.

The net clinical benefit of warfarin therapy overall and by individual risk factors using different weights for ICH

ICH weight = 1.5 (base case) ICH weight = 1 ICH weight = 2
Risk Factor Risk
Factor
Level		 Net
Clinical
Benefit		 95% CI Net
Clinical
Benefit		 95% CI Net
Clinical
Benefit		 95% CI
LCL UCL LCL UCL LCL UCL
All Patients All Patients 0.68 0.34 0.87 0.80 0.51 0.96 0.56 0.18 0.77
Age Group <65 (0.25) (0.65) 0.08 (0.15) (0.48) 0.14 (0.35) (0.81) 0.05
65-74 0.11 (0.37) 0.40 0.27 (0.16) 0.55 (0.05) (0.58) 0.27
75-84 1.00 0.44 1.40 1.09 0.59 1.44 0.92 0.29 1.34
≥ 85 2.34 1.29 3.30 2.51 1.62 3.37 2.17 0.93 3.18
Sex Male 0.13 (0.23) 0.37 0.28 (0.03) 0.49 (0.02) (0.43) 0.25
Female 1.44 0.90 1.75 1.52 1.02 1.79 1.35 0.75 1.72
Prior Stroke N 0.56 0.22 0.72 0.67 0.37 0.81 0.45 0.06 0.64
Y 2.48 0.75 4.22 2.69 1.12 4.42 2.27 0.36 4.09
Hypertension N 0.74 0.35 1.02 0.81 0.47 1.06 0.66 0.22 0.99
Y 0.65 0.20 0.90 0.80 0.40 1.04 0.49 (0.01) 0.77
CHF N 0.41 0.09 0.66 0.52 0.24 0.75 0.30 (0.08) 0.58
Y 1.28 0.56 1.68 1.42 0.76 1.78 1.14 0.35 1.58
Diabetes N 0.59 0.25 0.82 0.72 0.42 0.92 0.46 0.06 0.72
Y 1.07 0.15 1.59 1.15 0.32 1.63 0.99 (0.03) 1.56
CHADS2
Score		 0 (0.11) (0.44) 0.20 (0.07) (0.38) 0.20 (0.14) (0.53) 0.21
1 0.19 (0.27) 0.45 0.33 (0.06) 0.57 0.06 (0.50) 0.34
2 0.97 0.43 1.41 1.07 0.61 1.45 0.87 0.26 1.35
3 2.07 1.21 2.79 2.06 1.26 2.72 2.09 1.12 2.85
4-6 2.22 0.58 3.75 2.51 1.04 4.01 1.94 0.19 3.52

CHF=congestive heart failure; CI=confidence interval; LCL=lower confidence limit; UCL=upper confidence limit; CHADS2 is the acronym for the stroke risk scoring system for patients with atrial fibrillation where C=congestive heart failure, H=hypertension, A=age ≥75 years, D=diabetes, and S=prior stroke (risk factors C, H, A and D are given 1 point each, S is doubly weighted, hence S2)

For ICH weighted as 1, Net Clinical Benefit=(TE rateoff warfarin − TE rateon warfarin) − 1.0 × (ICH rateon warfarin − ICH rateoff warfarin), derived from adjusted rate differences shown in Table 2A

For ICH weighted as 1.5, Net Clinical Benefit=(TE rateoff warfarin − TE rateon warfarin) − 1.5 × (ICH rateon warfarin − ICH rateoff warfarin), derived from adjusted rate differences shown in Table 2A

For ICH weighted as 2, Net Clinical Benefit=(TE rateoff warfarin − TE rateon warfarin) − 2.0 × (ICH rateon warfarin − ICH rateoff warfarin), derived from adjusted rate differences shown in Table 2A