This is a prospective, multicentre observational follow-up study of PegIFN treatment unstained response in nucleoside experienced patients with Chronic Hepatitis B.Patients will join this study after finished following clinical trail about A Study of Combination or Sequential Treatment With PEGASYS (Peginterferon Alfa-2a) and Entecavir in Patients With HBeAg Positive Chronic Hepatitis B(OSST trail),A Real-World Study of Pegylated Interferon In Nucleoside-treated Patients With Chronic Hepatitis B (COST study), Combination Therapy With Interferon Plus Interleukin 2 and Hepatitis B Vaccine in Chronic Hepatitis B Patients(Endeavor study),A Prospective Clinical Trial in Chronic Hepatitis B Patients Nucleotide Analogues Experienced (Anchor A Study),Sequential/Combination Therapy in Nucleoside or Nucleotide Analogue (NA)-Suppressed Chronic Hepatitis B Patients (NPGV study).We plan to compare the HBsAg negative rate and maintenance rate,the occurrence of liver cirrhosis and the occurrence rate of hepatocellular carcinoma(HCC) related to hepatitis B virus(HBV) within five years between interferon group (including interferon alone or interferon combined with other drugs) and nucleoside analogues.Patients were divided into two groups based on whether they received interferon or not.

Patients who treated with nucleoside analogs, and previously took part in the OSST,COST,Endeavor, Anchor NPGV studies, were included in the observational study after they finished. The patients entered the following two observation groups based on previous studies: Group A: formerly interferon group (including interferon alone or interferon combined with other drugs); Group B: formerly nucleoside analogue treatment group. Each group was followed for five years.All patients were followed up for physical examination (vital signs, whole body examination) and laboratory assessment (HBsAg quantification, HBeAg quantification, HBV DNA, HBV immunology marker, blood routine, blood biochemistry, alpha fetoprotein, Fibroscan, liver Doppler) in every six month.

Inclusion Criteria:

1. Male and female patients from 18 to 65 years of age;
2. Have finished the OSST,COST,Endeavor, Anchor,NPGV studies;
3. Agree to participate in the study and sign the patient informed consent.

Exclusion Criteria:

1. patients have not participated in the OSST,Cost,Endeavor,Anchor or NPGV study ;
2. unable or unwilling to provide informed consent or follow the research requirements

Patients who treated with nucleoside analogs, and previously took part in the OSST,COST,Endeavor, Anchor,NPGV studies, were included in the observational study after they finished.