2.1 General Baseline Data Analysis
This study included 339 cases of obstructive jaundice. The normality of the sample data was determined using a normality test for measurement data. If the data were normally distributed, the mean ± standard deviation was used to represent the data, and an independent sample t-test was used for comparison between the two groups. If the data were not normally distributed, the median (25th percentile, 75th percentile) was used to represent the data, and a Wilcox test was used for comparison between the two groups. Categorical (qualitative) data were described statistically by frequency (percentage), and χ2 test or Fisher's exact test was used for comparison between groups, as shown in Table 1 below.
Table 1
Comparison of general clinical data between two groups of patients
variable_training | group 0(n = 178) | group 1(n = 93) | p_training | variable_validation | group 0(n = 40) | group 1(n = 28) | p_validation |
Age | 62.5 ± 14.01 | 65.67 ± 10.03 | 0.121 | Age | 61.27 ± 13.94 | 64.32 ± 6.52 | 0.232 |
Sex | | | 0.152 | Sex | | | 0.163 |
Male | 89 (50%) | 55 (59.14%) | | Male | 16 (40%) | 16 (57.14%) | |
Female | 89 (50%) | 38 (40.86%) | | Female | 24 (60%) | 12 (42.86%) | |
CEA | 1.83 (1.29,2.62) | 3.67 (2.26,5.86) | < 0.001 | CEA | 1.9 (1.22,2.25) | 3.51 (2.06,6.01) | < 0.001 |
CA125 | 11.82 (9.28,19.02) | 18.41 (11.85,38.53) | < 0.001 | CA125 | 12.31 (8.27,17.16) | 19.95 (14.43,33) | 0.001 |
CA199 | 64.28 (25.53,197.22) | 175.11 (57.37,580.9) | < 0.001 | CA199 | 37.94 (12.88,132.15) | 302.2 (49.26,1000) | 0.001 |
AFP | 2.36 (1.63,3.28) | 2.8 (2.03,3.93) | 0.003 | AFP | 2.24 (1.68,2.86) | 2.33 (1.49,3.42) | 0.636 |
TBIL | 54.2 (33.65,88.09) | 203.6 (111.1,273.2) | < 0.001 | TBIL | 48.52 (30.14,89.06) | 204.47 (128.5,303.1) | < 0.001 |
TP | 67.6 ± 6.33 | 65.31 ± 7.72 | 0.015 | TP | 67.74 ± 6.48 | 65.2 ± 7.95 | 0.151 |
ALT | 128.9 (61.71,258.78) | 96 (67,156.6) | 0.016 | ALT | 127.06 (70.21,258.29) | 68.5 (46,134.32) | 0.02 |
AST | 87.65 (49.72,195.81) | 83.51 (58,128.3) | 0.539 | AST | 95.64 (57.83,170.48) | 69.7 (54.98,109.87) | 0.154 |
NLR | 5.85 (2.95,11.19) | 3.36 (2.36,4.61) | < 0.001 | NLR | 6.09 (3.88,13.4) | 4.03 (2.82,6.48) | 0.049 |
Note: Group 1: benign obstructive jaundice group; Group 2: Malignant obstructive jaundice group; CEA, Carcinoembryonic antigen; AFP: alpha-fetoprotein; CA125: Carbohydrate antigen 125; CA153: Carbohydrate antigen 153; CA19-9: Carbohydrate antigen 19 − 9; TBIL: Total bilirubin; DBIL: Direct bilirubin; TP: total protein; ALT: alanine aminotransferase; AST: Aspartate transferase; NLR: Ratio of neutrophil to lymphocyte count. |
2.3 Influencing Factors of Benign and Malignant Obstructive Jaundice
Variables with P < 0.05 in the above training groups were included in a binary logistic regression analysis, and the results showed that there were significant differences between the two groups for CEA, DBIL, ALT, and NLR (P < 0.05). Details are shown in Table 2.
Table 2
Multivariate Logistic regression analysis of obstructive jaundice between different independent variable groups
Correlation factor | B | S.E | Wald | P | Exp(B) |
CEA | .402 | .098 | 17.008 | .000 | 1.495 |
CA125 | .018 | .011 | 2.745 | .098 | 1.018 |
CA199 | .000 | .000 | .002 | .967 | 1.000 |
AFP | .032 | .058 | .310 | .578 | 1.033 |
TBIL | .018 | .003 | 39.296 | .000 | 1.018 |
TP | − .002 | .031 | .006 | .939 | .998 |
ALT | − .005 | .002 | 5.889 | .015 | .995 |
NLR | − .225 | .057 | 15.583 | .000 | .798 |
Note: S.E: standard error; Wald: the value of the Waldka square; 95%CI: 95% confidence interval; CEA, Carcinoembryonic antigen; AFP: alpha-fetoprotein; CA125: Carbohydrate antigen 125; CA153: Carbohydrate antigen 153; CA19-9: Carbohydrate antigen 19 − 9; DBIL: Direct bilirubin; TP: total protein; ALT: alanine aminotransferase; NLR: Neutrophil/lymphocyte ratio. |
2.4 Establishment of Predictive Model for Benign and Malignant Obstructive Jaundice
These p < 0.01 indicators were included in a logistic stepwise regression equation (Table 3) to establish a comprehensive index for differentiating benign from malignant obstructive jaundice:
Table 3
Factors incorporated into prediction model for benign and malignant obstructive jaundice Note: S.E: standard error; Wald: the value of the Waldka square; 95%CI: 95% confidence interval; CEA, Carcinoembryonic antigen;DBIL: Direct bilirubin; NLR: Neutrophil/lymphocyte ratio.
Correlation factor | B | S.E | Wald | P | Exp(B) |
CEA | .444 | .099 | 20.083 | .000 | 1.558 |
TBIL | .017 | .003 | 45.716 | .000 | 1.017 |
NLR | − .208 | .054 | 15.060 | .000 | .812 |
constant | -2.848 | .420 | 45.899 | .000 | .058 |
p = exp(-2.848 + 0.444*CEA + 0.017*TBIL-0.208*NLR)/(1 + exp(-2.848 + 0.444*CEA + 0.017*TBIL-0.208*NLR))
The likelihood ratio test of the model showed that the regression model had statistical significance (χ² = 19.827, P < 0.01), and the goodness-of-fit test showed that the model fit was good (χ² = 177.995, P = 0.645). The adjusted determination coefficient R2 was 0.467. DBMOJCI ≥ > 0.42195 was used to diagnose malignant obstructive jaundice, and the prediction results of the regression model for the diagnosis of malignant obstructive jaundice showed that the AUC of the regression model was 0.920 (95% CI: 0.881 to 0.949), with a sensitivity and specificity of 79.57% and 93.26%, respectively, a positive predictive value of 95.74%, and a negative predictive value of 76.34%, as shown in Fig. 1. We evaluated prediction performance evaluation and the clinical applicability of the model, as shown in Supplementary Figs. 1 and 2.
2.4 Validation
The Hosmer-Lemeshow Goodness-of-Fit Test was performed on the model in the validation set with a chi-square value of 46.714, p = 0. 0.645. And adjusted the determination coefficient R2 = 0.467.Malignant obstructive jaundice was diagnosed with p ≥ 0.42195, and the prediction results of the regression model were shown as follows. The area under the training set ROC curve was 0.848 [0.748, 0.948], as shown in Fig. 2. Sensitivity and specificity were 0.90 and 0.79. The false negative rate was 0.100, the false positive rate was 0.2083, the concordance rate was 0.8235, Kappa was 0.6194, the positive predictive value was 0.6428, the negative predictive value was 0.9500, the corrected index was 0.6916, the positive likelihood ratio was 4.3200, and the negative likelihood ratio was 0.1263.
2.5 Comparative Analysis
We will compare the diagnostic performance of the model we established with other assessment modalities reported in previous literature, as shown in Table 4.
Table 4
Sensitivity and specificity of Evaluation model compared with other assessment modalities
Method | Patients | sensitivity (%) | specificity(%) | AUC |
Prediction model(p) | 339 | | | |
> 0.487 | | 76.34 | 95.51 | 0.92 |
> 0.69639 | | 64.52 | 97.19 | |
> 0.83 | | 50.54 | 98.31 | |
> 0.93042 | | 35.48 | 100 | |
Bilirubin, mmol/l | | | | |
> 85(Al-Mofleh 2004) | 126 | 98.6 | 59.3 | 0.74 |
> 100 (Giuseppe G 2011) | 1026 | 71.9 | 88.0 | 0.82 |
> 250 (Giuseppe G 2011) | | 31.9 | 98.0 | |
CA19-9, U/mL | | | | |
> 32( La Greca G 2012) | 102 | 82.3 | 45.0 | 0.71 |
> 70.5(Morris-Stiff G 2009) | 248 | 82.1 | 85.9 | 0.87 |
> 100( La Greca G 2012) | 102 | 68.6 | 64.7 | |
>90, After biliary drainage (Marrelli D 2009) | 128 | 61 | 95 | |
CA199/Tible( La Greca G 2012) | 102 | 49 | 78.4 | |
CA199/CRP( La Greca G 2012) | 102 | 76.5 | 68.6 | |
CA199, multiplier( Liu W20 18) | 508 | 67.8 | 80.7 | 0.815 |
CA199/Tible( Liu W20 18) | | 69.96 | 82.71 | 0.889 |
Combined CA199 and Tbile( Liu W20 18) | | | 93.2 | 80.5 |
Combine multiple indicators( Ince AT 2008) | 225 | 88.5 | 45.7 | |