D-Dimer Combined with Fibrinogen Predicts the Risk of Venous Thrombosis in Fracture Patients

Table 4

Sensitivity, specificity, positive predictive value, and negative predictive value of D-dimer, fibrinogen, and combination of D-dimer and fibrinogen based on the Youden index.

Variable	Value	Se	Sp	PPV	NPV	Accuracy
D2	0.375	0.752 (0.722, 0.781)	0.624 (0.615, 0.633)	0.144 (0.133, 0.154)	0.968 (0.963, 0.972)	0.634 (0.625, 0.643)
Fib	0.046	0.269 (0.239, 0.298)	0.777 (0.769, 0.785)	0.092 (0.081, 0.103)	0.927 (0.921, 0.932)	0.738 (0.730, 0.746)
D2 + FIB	0.271	0.668 (0.636, 0.700)	0.603 (0.594, 0.613)	0.124 (0.114, 0.133)	0.956 (0.951, 0.961)	0.608 (0.599, 0.618)
Q1
D2	0.450	0.844 (0.776, 0.912)	0.606 (0.588, 0.625)	0.083 (0.067, 0.099)	0.989 (0.984, 0.994)	0.616 (0.598, 0.634)
Fib	0.101	0.330 (0.242, 0.419)	0.771 (0.755, 0.787)	0.057 (0.039, 0.076)	0.965 (0.957, 0.973)	0.753 (0.737, 0.770)
D2 + FIB	0.318	0.688 (0.601, 0.775)	0.630 (0.611, 0.648)	0.073 (0.057, 0.089)	0.980 (0.973, 0.986)	0.632 (0.614, 0.650)
Q2
D2	0.445	0.735 (0.669, 0.800)	0.710 (0.693, 0.728)	0.147 (0.123, 0.170)	0.975 (0.968, 0.982)	0.712 (0.695, 0.729)
Fib	0.104	0.480 (0.407, 0.554)	0.624 (0.605, 0.642)	0.080 (0.063, 0.096)	0.947 (0.936, 0.957)	0.615 (0.597, 0.633)
D2 + FIB	0.336	0.701 (0.633, 0.768)	0.635 (0.616, 0.654)	0.115 (0.096, 0.134)	0.969 (0.961, 0.977)	0.639 (0.622, 0.657)
Q3
D2	0.321	0.659 (0.594, 0.723)	0.662 (0.643, 0.681)	0.142 (0.120, 0.164)	0.958 (0.949, 0.968)	0.662 (0.644, 0.680)
Fib	0.133	0.577 (0.510, 0.644)	0.556 (0.536, 0.575)	0.099 (0.082, 0.116)	0.939 (0.927, 0.952)	0.557 (0.538, 0.576)
D2 + FIB	0.275	0.529 (0.461, 0.597)	0.746 (0.729, 0.763)	0.150 (0.124, 0.176)	0.949 (0.939, 0.959)	0.729 (0.712, 0.746)
Q4
D2	0.318	0.806 (0.765, 0.847)	0.512 (0.492, 0.532)	0.191 (0.171, 0.211)	0.948 (0.937, 0.960)	0.549 (0.530, 0.567)
Fib	0.036	0.200 (0.158, 0.242)	0.836 (0.821, 0.850)	0.149 (0.117, 0.180)	0.880 (0.866, 0.893)	0.756 (0.740, 0.772)
D2 + FIB	0.247	0.530 (0.478, 0.582)	0.718 (0.700, 0.735)	0.212 (0.185, 0.239)	0.914 (0.902, 0.927)	0.694 (0.677, 0.711)

D2: D-dimer; FIB: fibrinogen; Se: sensitivity, Sp: specificity; PPV: positive predictive value; NPV: negative predictive value; Q1 (age ≤ 45), Q2 (45 < age ≤ 60), Q3 ((60 < age ≤ 70), and Q4 (age > 70);