Abstract: Objective To investigate the prediction of response in patients with low serum HBsAg level chronic hepatitis B （CHB） receiving peginterferon-α-2a （Peg-IFNα-2a） after nucleos（t）ide analogues （NAs） treatment. Methods 80 patients with CHB with low HBsAg level admitted to our hospital between April 2014 and April 2016, and they were randomly divided into the observation group and the control group with 40 cases in each by the randomized number table. All patients had been given NAs for a long time and had gained virologic response before enrollment. Patients in the control group was given entecavir,and those in the observation group was additionally given peg-IFNα-2a besides entecavir for 48 weeks. The multivariate analysis was performed, and the baseline serum HBsAg level was estimated for the virologic response at the end of treatment by the area under the curve（AUC） of receiver operating characteristic（ROC）. Results At the end of 48 weeks of treatment,serum HBsAg level and HBV DNA load were （1.5±0.3） lg U/ml and （0.1±0.1） lg U/ml,respectively,in the observation group,significantly lower than （2.0±0.2） lg U/ml and（1.3±0.3） lg U/ml in the control（P<0.05）,and serum HBsAg clearance rate and HBV DNA negative rate were 32.5% and 92.5%,respectively,in the observation group,significantly higher than 6.3% and 55.0% in the control （P<0.05）;the baseline serum HBsAg level was an independent factor for HBsAg clearance （OR: 0.337,95% CI: 0.026-0.652,P<0.05）;According to AUC analysis,the sensitivity,specificity,positive predictive value, negative predictive value and the accuracy rate were 0.85,0.68,67.2% and 85.3% and 72.5% when baseline HBsAg level being 2.0 lg U/ml as the cut-off value. Conclusions The peg-IFN-α-2a treatment can improve the clinical efficacy in CHB patients with low serum HBsAg level after NAs therapy,and the baseline HBsAg level has some predictive values for end of treatment response.

Key words: Chronic hepatitis B, Peginterferon-α-2a;, Serum HBsAg levels, HBsAg clearance, Therapy