The influence of insulin sensitivity and glucose tolerance on the effects of antiviral therapy for HCV remains unclear. The aim of the present study was (1) To elucidate the clinical and virological factors associated with sustained viral response in patients with combination therapy with PEG-IFN and ribavirin. (2) To clarify the influence of diabetes mellitus (DM), impaired glucose tolerance test (IGT) and insulin resistance (IR) on the HCV response to combination therapy with PEG-IFN and ribavirin. (3) To test the influence of combination therapy on HOMA IR

Total 300 treatment-naïve chronic hepatitis C patients will be enrolled. The prevalence of NIDDM, IGT and IR will be explored in this hospital-based study among the clinically defined chronic hepatitis C Taiwanese. The clinical manifestations of chronic hepatitis C in the biochemical, virological and histopathological aspects will be evaluated. Liver enzymes will be measured on a multichannel autoanalyzer. Virological markers for HCV including serum HCV RNA detected using a standardized automated qualitative PCR assay, HCV RNA genotypes determined for genotypes 1a, 1b, 2a, 2b and 3a and serum HCV RNA levels measured by using the branched DNA assay. The liver histology will be assessed for scoring the disease activity grade quantitatively according to the histological activity index (HAI). Patients are assigned a diagnosis of DM if there was documented use of oral hypoglycemic medication or insulin, random glucose in excess of 200 mg/dL, or fasting glucose greater than 126 mg/dL on two occasions. A standard oral glucose tolerance test (OGTT) will be performed. In addition to an OGTT, a history of diabetes mellitus by chart review and/or questionnaire will be also obtained. Standard antiviral therapy will be carried out with PEG-IFN, given subcutaneously weekly plus 1,000-1,200 mg of oral ribavirin daily. Patients will receive another 24 week of follow-up period to determine the virological response.

Inclusion Criteria:

1. Chronic hepatitis C patients with positive anti-HCV for more than 6 months and HCV RNA
2. No overt hepatic failure or decompensated liver cirrhosis (Child-Pugh class B or C) or hepatocellular carcinoma.

Exclusion Criteria:

1. Positive for hepatitis B surface antigen (HBsAg)or with concomitant human immunodeficiency virus infection
2. With other types of hepatitis including autoimmune hepatitis, primary biliary cirrhosis, sclerosing cholangitis, Wilson's disease, alpha 1-antitrypsin deficiency
3. Current or past history of alcohol abuse (80 mL ethanol per day)