The determination of GGT is the most reliable predictor of nonresponsiveness to interferon-alpha based therapy in HCV type-1 infection.

BACKGROUND

The critical analysis of baseline factors has been found to be useful to predict virologic nonresponse (NR), relapse, or sustained virologic response (SVR) in patients infected with hepatitis C virus (HCV) who receive antiviral therapy. In the present retrospective study we tried to find out whether gamma-glutamyltranspeptidase (GGT) may be one of the baseline factors which are of special predictive power. We analyzed, in patients with different treatment outcomes, the predictive power of established baseline factors either in combination with GGT or by evaluating the predictive value of GGT independently.

METHODS

Individual data from 632 patients chronically infected with HCV type 1 (n = 561) or type 2/3 (n = 71) were analyzed. All patients had received their first course of antiviral therapy and were treated with pegylated interferon α-2a or -2b plus ribavirin.

RESULTS

In patients with HCV type 1, a multivariate multinomial logistic regression analysis identified low GGT (p < 0.0001), high cholesterol (p < 0.0001), age ≤ 40 years (p < 0.0001), high alanine aminotransferase (p = 0.0006), low viremia (p = 0.0014), and absence of cirrhosis (p = 0.0164) as independent predictors. While these baseline factors heralded improved virologic response, high GGT, in contrast, was significantly associated with NR (p < 0.0001). A strong correlation was found between log(10) GGT and a scoring variable S (r = -0.26 for prediction of SVR, p < 0.001; r = 0.11 for prediction of NR, p = 0.016) summarizing predictive information from other baseline factors.

CONCLUSIONS

These findings prove the predictive sensitivity of GGT as an independent indicator of nonresponsiveness even at levels that are slightly above the normal range. This new predictive parameter may help to improve individualized therapy in HCV type-1 infection.