Background. Clinical implications of persistent alanine aminotransferase (ALT) elevation and associated factors in chronic hepatitis C (CHC) patients who achieved undetectable hepatitis C virus (HCV) RNA during pegylated interferon plus ribavirin (peg-IFN/RBV) therapy remain unknown. Methods. A total of 1113 CHC patients with undetectable HCV RNA during peg-IFN/RBV therapy were enrolled. Baseline characteristics associated with persistent on-treatment ALT elevation (POAE), and its impact on treatment outcomes, were investigated. Results. Of 1113 CHC patients, 254 (22.8%) had POAE. Among patients with HCV genotype 1 (HCV-1) who had complete early virologic response (EVR) and received 48 weeks of therapy, patients with POAE had a lower rate of sustained virologic response (SVR) than those without POAE (44.1% vs 74.0%; P = .0002). Multivariate analyses showed that body mass index >= 27 kg/m(2), ALT level >= 3 times the upper limit of normal, aspartate aminotransferase to platelet ratio index score >= 1.5, hepatic fibrosis >= F3, and hepatic steatosis >= S2 were independent factors associated with POAE after viral clearance. Conclusions. POAE is common in CHC patients during therapy. HCV-1 patients with POAE have a lower SVR rate to 48-week therapy if they achieve complete EVR. Advanced hepatic fibrosis, obesity, and steatosis are factors associated with POAE in these patients. ; 微生物學科暨研究所 ; 醫學院 ; 期刊論文