Factors affecting serum concentrations of hepatitis C virus (HCV) RNA in HCV genotype 1-infected patients with chronic hepatitis

The serum concentration of hepatitis C virus (HCV) RNA is usually stable (4 to 8 log₁₀ IU/ml) in untreated patients with chronic hepatitis C. While this baseline HCV RNA concentration ([HCV RNA]_BL) is predictive of a sustained virologic response to treatment, its determinants are only partially identified. We therefore analyzed the baseline characteristics of 2,472 HCV genotype 1-infected patients to identify correlations with gender, age, race, weight, body mass index (BMI), HCV acquisition mode, HCV subtype, alanine aminotrans-ferase concentration, or histopathologic changes in the liver. After separation of the data according to four [HCV RNA]_BL groups (≤5.0, >5.0 to 5.6, >5.6 to 5.9, and >5.9 log₁₀ IU/ml), we determined that increasing [HCV RNA]_BL correlated (P < 0.05) with increasing proportions of patients who were male, >40 years of age, or heavier (a weight of >85 kg or a BMI of >27 kg/m²). Histologic activity index (HAI) data were available for 1,304 of these patients: increasing [HCV RNA]_BL correlated with higher fibrosis and necrosis-inflammation scores. As a continuous variable, [HCV RNA]_BL correlated with age, gender, weight (continuous or ≤85 versus >85 kg), BMI (continuous or ≤27 versus >27 kg/m²), subtype, fibrosis score, and necrosis-inflammation score; however, multiple-regression analysis yielded P values of <0.1 only for age, gender, BMI (≤27 versus >27 kg/m ²), and fibrosis score. While our findings are suggestive of a role for these factors in maintenance of the pretreatment state of HCV infection, the multiple-regression model accounted for only ≤4.6% of the [HCV RNA] _BL differences between individuals (R² = 0.046 for 1,304 patients with HAI scores; 0.043 for all 2,472 patients).