2.1 Characteristic of HBeAg (+) and HBeAg (−) patients
We enrolled 1020 patients in this study from January 2011 to December 2013, including 881 males and 139 females; 252 patients were HBeAg-positive (HBeAg (+)) and 768 were HBeAg-negative (HBeAg (−)); 535 had high HBV DNA levels and 585 had low HBV DNA levels. The characteristics of the patients was shown in table 1. The values of age, the platelet count (PLT), aspartate aminotransferase (AST), and high HBV DNA levels are significant between the patients of HBeAg(+) and HBeAg(-). The HBeAg(+) patients was younger, lower PLT levels, and higher AST levels than the HBeAg(-) patients. In contrast, the white blood cell (WBC) count and the levels of hemoglobin (HGB), total bilirubin (TB), alanine aminotransferase (ALT), albumin (ALB), and prothrombin time wasn’t significant. From Fig. 1-A, evaluating the CHB patients with a high HBV DNA levels by HBeAg(+) might be reliable, for the area of under the curve (AUC) was 0.622.
2.2 Characteristic in different HBV DNA levels
Table 1 showed the feature of high HBV DNA levels and low HBV DNA levels. The difference of PLT, AST, ALT, and ALB were significant between the groups, and the ROC of predicting the patients with a high HBV-DNA level was shown in Fig. 1-B. The AUC of AST, ALT, ALB, and PLT was 0.635, 0.642, 0.432, and 0.473, respectively, and the optimal cutoff points were 46.5 IU/L, 42.5 IU/L, 25.5 g/L, and 74.5 × 109/L, respectively. The levels of AST and ALT were higher in high HBV DNA group, and the levels of PLT and ALB were lower. Furthermore, the logistic regression multivariate analyses showed the PLT and AST weren’t significant.
2.3 The different HBV DNA levels in HBeAg (+) patients
The difference of the HBeAg(+) patients with high and low HBV DNA levels was shown in table 2. The sex, age, PLT, WBC, TB, AST, and ALT were not significant. The variables of HGB, ALT, and HBeAg were significant, and the AUC was 0.394, 0.379, and 0.787, respectively, with the optimal cut-off points being 170.5 g/L, 25.0 g/L, and 16.15 S/CO, respectively, (Fig. 1-C).
2.4 The different HBV DNA levels in HBeAg (-) patients
Table 2 summarized the HBV DNA levels characteristics of HBeAg(-) patients. The variables of TB, AST, and ALT were significantly difference between the groups. The AUC of these variables was 0.511, 0.628, and 0.655, respectively (Fig. 1-D), and the cutoff values were 11.15 umol/L, 36.5 U/L, and 42.5 U/L, respectively.
2.5 The logistic regression multivariate analysis in CHB patients and HBeAg(-) patients
Table 3 showed the logistic regression multivariate analysis of the 1020 CHB patients and the paitents with HBeAg(-). Through the logistic regression multivariate analysis and univariate analysis, the independent risk factors of CHB patients with high HBV-DNA level were ALT, ALB and HBeAg (table 3). And we could draw the predict model of the CHB patients with a high HBV DNA level as:
M1 (high HBV DNA levels) = 1.412 × (1 for HBeAg-positive > 16.15 S/CO or 0 for others) + 0.004 × (1 for ALT > 42.5 IU/L or 0 for others) − 0.029 × (1 for ALB > 25.5 g/L or 0 for others) + 0.779
The ROC of the predictive model M1 was shown in Fig. 2-A. The AUC was 0.606, and the cutoff value was 0.752.
On the other hand, for the logistic regression multivariate analysis, only TB and ALT were significant for the patients with HBeAg(-) (table 3). Combining with the univatiate analysis (table 2), the level of TB and ALT were the independent risk factors for the HBeAg(-) patients with high HBV-DNA level. Following the result, we drew the predict model of HBeAg(-) patients with a low HBV DNA levels as:
M2 (low levels of HBV DNA) = 0.385 − 0.005 × (1 for ALT > 36.5 IU/L or 0 for others) − 0.006 × (1 for TB > 11.15 umol/L or 0 for others)
The ROC of the predictive model M2 was shown in Fig. 2-B. The AUC was 0.609, and the cutoff value was 0.3765.