OBJECTIVETo study the incidence and the predictive factors of HBV polymerase YMDD variation among patients with chronic hepatitis B and liver cirrhosis during lamivudine therapy.

METHODSThe clinical data and serial sera of 313 chronic HBV infected patients (249 chronic hepatitis B and 64 liver cirrhosis) treated with lamivudine were collected. YMDD variations were determined by mispairing PCR-RFLP assay. The data were analyzed using SPSS software.

RESULTSThe cumulative rates of variation among patients with chronic hepatitis B and liver cirrhosis were 8.84% and 17.19%, 20.91% and 32.40%, 26.92% and 39.56%, 26.92% and 58.79% after 12, 24, 36 and 48 months of lamivudine treatment, respectively. The results of log-rank test and Cox's proportional hazard model analysis indicated that lamivudine monotherapy, low ALT level, high HBV DNA level, and the patients with liver cirrhosis at baseline were significantly related to an occurrence of YMDD variation.

CONCLUSIONThis study suggests that lower ALT and higher HBV DNA levels at baseline before lamivudine treatment, lamivudine monotherapy without combining alpha-interferon, and the patients with liver cirrhosis seem to be statistically significant for predicting the occurrence of YMDD variation.