title: Natural history of HCV infection.
abstract: BACKGROUND
  There is much controversy surrounding the natural history of hepatitis C virus (HCV) infection.
  
  
  OBJECTIVE
  The aim of this review was to review the natural history of HCV infection.
  
  
  METHODS
  Published English literature was searched via pubmed and then reviewed.
  
  
  RESULTS
  Approximately, 75-85% of HCV-infected persons will progress to chronic HCV infection. The rate of chronic HCV infection is affected by a person's age, gender, race, and viral immune response. Once chronic HCV infection develops, there are external and host factors that can increase the risk of progression of liver disease. Progression of chronic HCV infection is not linear in time, probably because many cofactors change the rate of development of fibrosis, cirrhosis, and hepatocellular carcinoma. Factors linked with aggressive disease progression include age at infection, duration of infection, heavy alcohol use, co-infections with HIV or hepatitis B virus, male sex, steatosis, insulin resistance (and factors associated with the metabolic syndrome), and host genetics. However, the relative importance of many and varied factors remains uncertain, and further research efforts should be directed toward design of predictive models for effective risk stratification. Interferon-based therapy, particularly among those achieving a sustained virologic response (SVR), is associated with improved fibrosis and inflammation scores, reduced incidence of hepatocellular carcinoma, and prolonged life expectancy.
  
  
  CONCLUSIONS
  Despite the progress in understanding the factors affecting the natural history of HCV infection, a great deal remains to be learnt.
authors.affiliation: Department of Hepatology, Institute of Liver and Biliary Sciences, D1 Vasant Kunj, New Delhi, India. shivsarin@gmail.com.
authors.forename: Shiv K
authors.initials: SK
authors.lastname: Sarin
authors.affiliation: Department of Hepatology, Institute of Liver and Biliary Sciences, D1 Vasant Kunj, New Delhi, India.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
keywords: Acute hepatitis C; Chronic hepatitis C; Hepatitis C; Natural History