Objective:To analyze Hepatitis B virus(HBV)drug resistance mutations in patients with chronic hepatitis B(CHB)infection who have undergone long-term monotherapy with Entecavir(ETV)and those receiving combination therapy with ETV and Lamivudine(LAM), and to explore the related factors affecting HBV drug resistance mutations.Methods:The study retrospectively analyzed patients with CHB, compensated cirrhosis, decompensated cirrhosis, and liver cancer who received long-term nucleotide analogue antiviral therapy at the Fifth Medical Center of PLA General Hospital from August 2012 to August 2019.The patients were divided into an ETV monotherapy group and a combined LAM+ETV therapy group.Chi-square tests, independent sample t-tests, and Wilcoxon rank-sum tests were used to compare the clinical baseline characteristics and HBV drug resistance mutation features between the two therapy groups.A multivariate logistic regression model was used to analyze the factors related to HBV drug resistance mutations. Results:A total of 533 patients were enrolled in this study, 357 in the ETV monotherapy group and 176 in the LAM+ETV group. The ETV monotherapy group had 122 (34.17%) patients with resistance mutations, while the LAM+ETV group had 126 (71.59%).In general, the difference in gene mutation rate between the two therapy groups was statistically significant( χ2=66.337, P<0.001). The median age and alanine aminotransferase levels of patients with drug resistance mutations in the two therapy groups were higher than those in the non-mutation group[( t=-4.743, P<0.001)/( Z=-4.809, P<0.001), ( Z=-2.667, P=0.007)/( Z=-2.001, P=0.045)].Age( OR=1.044, 95% CI:1.023-1.066), compensated cirrhosis( OR=2.163, 95% CI:1.193-3.922), liver cancer( OR=4.017, 95% CI:2.170-7.436) and the treatment regimen( OR=6.075, 95% CI:3.889-9.489) were associated with drug resistance gene mutations( P<0.001).The mutation rates in different stages of chronic liver disease(CHB, cirrhosis, and liver cancer)showed statistically significant( χ2=41.038, P<0.001; χ2=15.894, P<0.001).The overall mutation rates of ETV-related genes in the two therapy groups were 25.49% and 32.39%, respectively.Additionally, 10 mutation sites and 38 variant combinations were identified, containing five common combinations being rtL180M, rtM204V, rtS202G;rtL180M, rtM204V, rtT184A; rtL180M, rtM204V, rtT184L;rtM204I and rtL180M, rtM204V. Conclusion:In CHB patients undergoing long-term therapy, the rate of HBV resistance mutations is higher in those receiving ETV and LAM combination therapy than in those receiving ETV monotherapy.Monitoring older patients and those with cirrhosis or liver cancer is especially important for preventing resistance mutations.

Objective:To analyze Hepatitis B virus(HBV)drug resistance mutations in patients with chronic hepatitis B(CHB)infection who have undergone long-term monotherapy with Entecavir(ETV)and those receiving combination therapy with ETV and Lamivudine(LAM), and to explore the related factors affecting HBV drug resistance mutations.Methods:The study retrospectively analyzed patients with CHB, compensated cirrhosis, decompensated cirrhosis, and liver cancer who received long-term nucleotide analogue antiviral therapy at the Fifth Medical Center of PLA General Hospital from August 2012 to August 2019.The patients were divided into an ETV monotherapy group and a combined LAM+ETV therapy group.Chi-square tests, independent sample t-tests, and Wilcoxon rank-sum tests were used to compare the clinical baseline characteristics and HBV drug resistance mutation features between the two therapy groups.A multivariate logistic regression model was used to analyze the factors related to HBV drug resistance mutations. Results:A total of 533 patients were enrolled in this study, 357 in the ETV monotherapy group and 176 in the LAM+ETV group. The ETV monotherapy group had 122 (34.17%) patients with resistance mutations, while the LAM+ETV group had 126 (71.59%).In general, the difference in gene mutation rate between the two therapy groups was statistically significant( χ2=66.337, P<0.001). The median age and alanine aminotransferase levels of patients with drug resistance mutations in the two therapy groups were higher than those in the non-mutation group[( t=-4.743, P<0.001)/( Z=-4.809, P<0.001), ( Z=-2.667, P=0.007)/( Z=-2.001, P=0.045)].Age( OR=1.044, 95% CI:1.023-1.066), compensated cirrhosis( OR=2.163, 95% CI:1.193-3.922), liver cancer( OR=4.017, 95% CI:2.170-7.436) and the treatment regimen( OR=6.075, 95% CI:3.889-9.489) were associated with drug resistance gene mutations( P<0.001).The mutation rates in different stages of chronic liver disease(CHB, cirrhosis, and liver cancer)showed statistically significant( χ2=41.038, P<0.001; χ2=15.894, P<0.001).The overall mutation rates of ETV-related genes in the two therapy groups were 25.49% and 32.39%, respectively.Additionally, 10 mutation sites and 38 variant combinations were identified, containing five common combinations being rtL180M, rtM204V, rtS202G;rtL180M, rtM204V, rtT184A; rtL180M, rtM204V, rtT184L;rtM204I and rtL180M, rtM204V. Conclusion:In CHB patients undergoing long-term therapy, the rate of HBV resistance mutations is higher in those receiving ETV and LAM combination therapy than in those receiving ETV monotherapy.Monitoring older patients and those with cirrhosis or liver cancer is especially important for preventing resistance mutations.