To investigate the diagnostic efficacy of quantitative detection of hepatitis B virus surface antigen (HBsAg) in patients with hepatitis B relapse after entecavir withdrawal.

Total of 80 patients with chronic hepatitis B (CHB) who received antiviral treatment with entecavir in Dongfang Hospital of Hainan Province from January 2013 to January 2016 were analyzed, retrospectively. The patients were divided into recurrence group (60 cases) and non-recurrence group (20 cases). The virological indexes including HBV DNA load and HBsAg determination were compared between the two groups. The influencing factors of relapse after entecavir treatment were analyzed by Cox regression model. The value of quantitative HBsAg detection after treatment in predicting the recurrence of patients with entecavir treatment was evaluated by ROC curve.

A total of 60 cases (75.00%) had virological recurrence during the 24-month follow-up, with the median recurrence time of 9.5 (5-24) months. There was no significant difference in age, sex ratio, body mass index, history of CHB and AFP between recurrent group and non-recurrence group (t= 0.854,χ²= 1.077,t = 0.749,t= 1.354,t= 1.499;P= 0.396, 0.299, 0.456, 0.180, 0.138). The positive rate of HBeAg, cirrhosis, family history of hepatitis B, HBV DNA load before treatment, HBsAg quantification after treatment and HBsAg positive rate in recurrence group were significantly higher than those in the non-recurrence group (χ²= 4.364, 6.667, 4.689,t= 4.096, 2.040, 8.219, 5.760;P= 0.037, 0.010, 0.030, 0.043,< 0.001, 0.016), but the medication time was significantly lower than that of non-recurrence group (t= 2.006,P= 0.048), with significant differences. Multivariate Cox regression analysis showed that cirrhosis (HR= 1.587,P= 0.041), HBeAg positive (HR= 1.742,P= 0.044) and HBsAg quantitative (HR= 2.606,P= 0.008) were independent risk factors for the relapse after entecavir treatment. ROC curve showed that the area under the curve of HBsAg quantification (AUC= 0.902,P< 0.001) was higher than that of semi-quantitative detection (AUC= 0.650,P = 0.046), with significant differences. The best cut-off point of HBsAg quantification was 2.03 log₁₀IU/ml. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value were 91.25%, 91.67%, 90%, 96.49% and 78.26%, respectively.

Liver cirrhosis, HBeAg positive and high HBsAg levels after treatment are independent risk factors for the relapse of hepatitis B after entecavir withdrawal. The quantitative detection of HBsAg for predicting the recurrence of patients with entecavir withdrawal had a high diagnostic efficacy.