Table 1.

Demographic and clinical information in the derivation and internal validation cohorts

	Derivation	Internal Validation
Demographic Variables	(N=969)	(N=244)
Male, N (%)	545 (56.2)	144 (59)
African Origin, N (%)	95 (9.8)	28 (11.5)
Caucasian Race, N (%)	818 (84.4)	207 (84.8)
Asian Race, N (%)	28 (2.9)	6 (2.5)
Other/Unknown Race, N (%)	28 (2.9)	3 (1.2)
Allele Frequencies
VKORC1-1639 G> A	35.2%	39.2%
CYP2C9*2	10.4%	11.5%
CYP2C9*3	5.9%	5.5%
Indication
Atrial Fibrillation/Flutter, N (%)	306 (31.6)	81 (33.2)
Orthopedic Surgery, N (%)	264 (27.2)	61 (25.0)
DVT or PE, N (%)*	251 (25.9)	69 (28.3)
Valve Replacement, N (%)	32 (3.3)	5 (2.0)
Stroke, N (%)	17 (1.8)	6 (2.5)
Other or Missing Indication, N (%)	99 (10.2)	22 (9.0)
Clinical Variables
Age, mean (SD), years†	62 (14.2)	61 (14.5)
Height, mean (SD), cm‡	170 (10.4)	173 (10.9)
Weight, mean (SD), kg§	87.5 (22.4)	86.7 (23.3)
Therapeutic Warfarin Dose, geometric mean (SD), mg/week	32.1 (1.6)	31.7 (1.5)
INR on day 4, geometric mean (SD) ‡	1.8 (1.4)	1.9 (1.4)
INR on day 5, geometric mean (SD)	1.9 (1.4)	1.9 (1.3)
Target INR, mean (SD)	2.5 (0.2)	2.5 (0.2)
1st Warfarin Dose, mean (SD), mg	7.7 (3)	7.6 (3)
2nd Warfarin Dose, mean (SD), mg	6.6 (2.8)	6.7 (2.9)
3rd Warfarin Dose, mean (SD), mg	5.1 (2.6)	5.0 (2.4)
Fluvastatin Use, N (%)	7 (0.7)	1 (0.4)
Amiodarone Use, N (%)	31 (3.2)	8 (3.3)
Inducer Use, N (%)║	7 (0.7)	1 (0.4)
Current Smoker, N (%)	101 (10.4)	27 (11.1)
Liver Disease, N (%)¶	15 (1.5)	4 (1.6)
Diabetes, N (%)	79 (8.2)	21 (8.6)

^*DVT is Deep Venous Thrombosis; PE is Pulmonary Embolism.

^†SD is Standard Deviation.

^‡INR is the International Normalized Ratio.

^║Rifampin or carbamazepine.

^¶Liver Disease is hepatic cirrhosis, a two-fold elevation of any liver transaminase, or an albumin < 3.6.