Prediction of the response of chronic hepatitis C to interferon alfa: a statistical analysis of pretreatment variables.

Pretreatment variables that could predict the response of chronic hepatitis C to interferon alfa treatment have not been fully assessed. Eighteen baseline variables were evaluated in a series of 100 consecutive patients treated with a 12 month course of interferon alfa. For the purposes of this study, response was defined as the return to normal of aminotransferase activities before the third month of treatment. Seventy per cent of the patients responded to treatment. Six variables were associated with an increased likelihood of response assessed by univariate analysis. With stepwise multiple regression analysis assessment, however, only three variables remained independently predictive of response: low gamma glutamyltransferase (gamma GT) activities (p < 0.001), absence of obesity (p = 0.005), and absence of cirrhosis (p = 0.01). The response rate in patients with gamma GT activities < 0.66 mu kat/l (n = 55) was 78% and 60% in patients with values > 0.66 mu kat/l (n = 45) (p = 0.048). Response was attained in 75% of non-obese patients (n = 80), compared with only 50% of obese patients (n = 20) (p = 0.03). Finally, 80% of patients without cirrhosis (n = 76) responded, while among those with cirrhosis (n = 24) the response rate was only 37% (p < 0.001). All 23 patients without cirrhosis, <40 years old, and with gamma GT activities <0.66 mu kat/l responded to treatment, while only 28.5% of 14 patients with cirrhosis, >40 years old, and with gamma GT activities >0.66 mu kat/l responded to interferon alfa (p<0.001). Those findings may be useful when evaluating interferon alfa trials and it is suggested that this treatment should be applied early in the course of chronic hepatitis C.