Table 1 Statistics on the factors in the training, internal validation, and external validation dataset (i.e., Set A, B, and C).

From: Warfarin maintenance dose prediction for Chinese after heart valve replacement by a feedforward neural network with equal stratified sampling

Characteristic (unit)

Training set (N = 15,248)

Internal validation set (N = 1906)

External validation set (N = 1906)

Mean ± SD/N (%)

Mean ± SD/N (%)

P-value

Mean ± SD/N (%)

P-value

Initial dose (mg/day)

2.93 ± 0.72

2.93 ± 0.70

1.00

2.66 ± 0.52

< 0.001

Albumin (g/L)

41.59 ± 4.42

41.45 ± 4.44

0.19

41.29 ± 4.24

0.005

Creatinine (μmol/L)

77.26 ± 19.15

76.84 ± 19.02

0.37

80.81 ± 20.29

< 0.001

APPT (s)

31.21 ± 7.65

31.55 ± 7.37

0.067

30.89 ± 5.71

0.077

Starting time of anticoagulation (X days after surgery) (days)a

2

2

0.26

2

< 0.001

Type of disease

  

0.24

 

< 0.001

Rheumatic heart disease

12,664 (83.05)

1573 (82.53)

 

1563 (82.00)

 

Degenerative mitral valve disease

617 (4.05)

79 (4.14)

 

60 (3.15)

 

Degenerative aortic valve disease

970 (6.36)

133 (6.98)

 

87 (4.56)

 

Congenital heart disease

13 (0.09)

0

 

0

 

Degenerative cardiac conduction system disease

564 (3.70)

72 (3.78)

 

87 (4.56)

 

Ischemic heart disease

17 (0.11)

6 (0.31)

 

1 (0.05)

 

Infective endocarditis

204 (1.34)

15 (0.79)

 

39 (2.05)

 

Secondary valvular heart disease

89 (0.58)

12 (0.63)

 

36 (1.89)

 

Traumatic valvular heart disease

8 (0.05)

0

 

0

 

Dilated cardiomyopathy

3 (0.02)

0

 

0

 

Hypertrophic cardiomyopathy

9 (0.06)

1 (0.05)

 

4 (0.21)

 

Systemic autoimmune disease

90 (0.59)

15 (0.79)

 

29 (1.53)

 

Tricuspid valve disease

  

0.34

 

< 0.001

Stenosis

165 (1.08)

21 (1.11)

 

20 (1.05)

 

Insufficiency

7610 (49.91)

993 (52.10)

 

1087 (57.03)

 

Stenosis and insufficiency

137 (0.90)

17 (0.89)

 

18 (0.94)

 

Method of initial dosing

  

0.12

 

< 0.001

Saturated dose

2647 (17.36)

304 (15.95)

 

70 (3.67)

 

General dose

12,601 (82.64)

1602 (84.05)

 

1836 (96.33)

 
  1. APPT activated partial thromboplastin time, SD standard deviation, Saturated dose dose ranging from 5 to 10 mg/day; General dose, dose ranging from 2.5 to 5 mg/day.
  2. aStarting time of anticoagulation (X days after surgery) (days) were showed by median because of its right skewed distribution. Continuous variables materials were analyzed by using independent sample t test; Categorical data materials were analyzed by using chi-square analysis. The starting time of anticoagulation was analyzed by using Wilcoxon rank-sum test; The type of disease was analyzed by using Monte Carlo method.
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