Alanine aminotransferase flare-up in hepatitis C virus carriers with persistently normal alanine aminotransferase levels in a hyperendemic area of Japan.

BACKGROUND: The clinical features of hepatitis C virus (HCV) carriers with persistently normal alanine aminotransferase (PNALT) levels (ALT < or = 34 IU/l) have not been fully elucidated. We investigated clinical factors associated with ALT flare-up in PNALT individuals in a HCV hyperendemic area of Japan.

METHODS: We analyzed 101 HCV carriers who had PNALT between 1993 and 2000. The first occurrence of ALT flare-up (ALT > or = 35 IU/l) between 2001 and 2005 was evaluated by the Kaplan-Meier method. Multivariate analysis of factors predicting ALT flare-up were conducted using Cox proportional hazards models.

RESULTS: The mean follow-up period was 2.8 years, and the 5-year cumulative incidence of ALT flare-up was estimated to be 31.8%. In multivariate analysis, an ALT level of 20-34 IU/l and a high serum ferritin level (> or =90 ng/ml) in the most recently available data up to the year 2000, as well as H63D heterozygosity in the HFE gene, were independently and strongly associated with the incidence of ALT flare-up (Hazard ratios = 5.6, 3.1, and 4.8, respectively). In addition, HFE H63D heterozygosity was significantly associated with higher serum ferritin levels in subjects with PNALT (153.8 + or - 73.3 ng/ml in subjects with the 63HD genotype vs. 89.4 + or - 51.3 ng/ml in subjects with the 63HH genotype, P = 0.043).

CONCLUSIONS: HCV carriers with PNALT in this population were at risk for ALT flare-up. Basal ALT levels, serum ferritin levels, and HFE polymorphism are potentially important predictors of ALT flare-up.