RESUMEN
The risk of cirrhosis in HCV and HBV-related liver diseases is higher in males than in females ; it increases exponentially after the age of 40 for the two genders. Alcohol consumption exceeding 50 gr per day multiplies cirrhosis risk by 6.0 in HBV patients and by 2.4 in HCV patients. B and C virus liver-related diseases are worsened by HIV co-infection particularly in patients with CD4 count lower than 200 per ml. Steatosis due to high body mass index (BMI) and/or metabolic syndrome is a newly described risk factor for cirrhosis in HBV and HCV patients and for hepatocellular carcinoma in HCV patients. Steatosis may become in a near future one of the major predicting factors of severity for chronic liver disease. The knowledge of worsening factors in patients suffering from chronic B and C viral hepatitis must lead clinicians to consider specific therapeutics against these factors and antiviral treatment even in case of borderline indication.