title: Occult hepatitis B infection in Portuguese patients with chronic hepatitis C liver disease:  prevalence and clinical significance.
abstract: BACKGROUND
  Occult hepatitis B virus (HBV) infection, defined as the presence of HBV DNA in the liver (with detectable or undetectable HBV DNA in the serum), has been reported in patients with chronic hepatitis C. Some data suggest its association with a more severe liver disease and a worse response to interferon therapy in this subgroup of patients. However, the clinical significance of this condition is still under debate.
  
  
  OBJECTIVE
  To determine the prevalence of occult HBV infection and its clinical significance in patients with chronic hepatitis C liver disease.
  
  
  METHODS
  A prospective analysis of consecutive outpatients with chronic hepatitis C who underwent a liver biopsy recruited between January 2008 and June 2011 was carried out. Data included patient's sex and age, source of hepatitis C virus (HCV) infection, HCV genotype and viral load, presence of serologic markers of previous HBV infection, HBV DNA presence in the liver, histologic findings, and response to interferon and ribavirin treatment. HBV DNA and HCV RNA detection were carried out using a sensitive commercially available PCR kit. HBV DNA was tested in liver samples using a nested PCR procedure.
  
  
  RESULTS
  One hundred patients were included, 73% men, mean age 49 ± 11.9 years. Most patients had a genotype 1, with a high viral load, HCV infection. Of the patients, 33% had HBV serologic markers of past infection. The presence of HBV DNA in liver samples was found in 57% of the patients. No statistically significant difference in the epidemiological, histological, or virological or response to therapy data was found in patients with occult HBV infection.
  
  
  CONCLUSIONS
  Occult HBV infection occurred in a high percentage of patients but was not clinically significant.
authors.affiliation: Setúbal Hospital Center, Setúbal, Portugal. claudiamarcal@gmail.com
authors.forename: Claudia
authors.initials: C
authors.lastname: Cardoso
authors.forename: Ana L
authors.initials: AL
authors.lastname: Alves
authors.forename: Fátima
authors.initials: F
authors.lastname: Augusto
authors.forename: Ricardo
authors.initials: R
authors.lastname: Freire
authors.forename: Carlos
authors.initials: C
authors.lastname: Quintana
authors.forename: Matilde
authors.initials: M
authors.lastname: Gonçalves
authors.forename: Ana P
authors.initials: AP
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D002353:Carrier State / Q000821:virology; D060085:Coinfection; D004279:DNA, Viral / Q000032:analysis; D004359:Drug Therapy, Combination; D005260:Female; D016174:Hepacivirus / Q000302:isolation & purification; D006509:Hepatitis B / Q000150:complications* / Q000188:drug therapy / Q000821:virology; D006515:Hepatitis B virus / Q000302:isolation & purification; D019698:Hepatitis C, Chronic / Q000150:complications* / Q000188:drug therapy / Q000821:virology; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D008099:Liver / Q000821:virology; D008297:Male; D008875:Middle Aged; D011174:Portugal; D011446:Prospective Studies; D012254:Ribavirin / Q000627:therapeutic use; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D004279:DNA, Viral; D012254:Ribavirin; D007372:Interferons