Objective: To investigate the demographic characteristics and clinical influencing factors which associates with the occurrence probability of persistent or intermittent hypoviremia (LLV) in patients with chronic hepatitis B (CHB) treated with nucleos(t)ide analogues (NAs). Methods: A single-center retrospective analysis was performed on patients with CHB who received outpatient NAs therapy forā„48 Ā± 2 weeks. According to the serum hepatitis B virus (HBV) DNA load at 48Ā±2 weeks treatment, the study groups were divided into LLV (HBV DNA < 20 IU/ml and < 2 000 IU/ml) and MVR group (sustained virological response, HBV DNA < 20 IU/ml). Demographic characteristics and clinical data at the start of NAs treatment (considered as baseline) were retrospectively collected for both patient groups. The differences in the reduction of HBV DNA load during treatment was compared between the two groups. Correlation and multivariate analysis were further conducted to analyze the associated factors influencing the LLV occurrence. Statistical analysis was performed using the independent samples t-test, c2 test, Spearman analysis, multivariate logistic regression analysis, or area under the receiver operating characteristic curve. Results: A total of 509 cases were enrolled, with 189 and 320 in the LLV and MVR groups, respectively. Compared to patients with MVR group at baseline: (1) the demographics characteristics of patients showed that LLV group was younger in age (39.1 years, P = 0.027), had a stronger family history (60.3%, P = 0.001), 61.9% received ETV treatment, and higher proportion of compensated cirrhosis (20.6%, P = 0.025) at baseline; (2) the serum virological characteristics of patients showed that LLV group had higher HBV DNA load, qHBsAg level, qHBeAg level, HBeAg positive rate, and the proportion of genotype C HBV infection but decreased HBV DNA during treatment (P < 0.001) at baseline; (3) the biochemical characteristics of patients showed that LLV group had lower serum ALT levels (P = 0.007) at baseline; (4) the noninvasive fibrosis markers of patients showed that LLV group were characterized by high aspartate aminotransferase platelet ratio index (APRI) (P = 0.02) and FIB-4 (P = 0.027) at baseline. HBV DNA, qHBsAg and qHBeAg were positively correlated with LLV occurrence (r = 0.559, 0.344, 0.435, respectively), while age and HBV DNA reduction were negatively correlated (r = -0.098, -0.876, respectively). Logistic regression analysis showed that ETV treatment history, high HBV DNA load at baseline, high qHBsAg level, high qHBeAg level, HBeAg positive, low ALT and HBV DNA level were independent risk factors for patients with CHB who developed LLV with NAs treatment. Multivariate prediction model had a good predictive value for LLV occurrence [AUC 0.922 (95%CI: 0.897 ~ 0.946)]. Conclusion: In this study, 37.1% of CHB patients treated with first-line NAs has LLV. The formation of LLV is influenced by various factors. HBeAg positivity, genotype C HBV infection, high baseline HBV DNA load, high qHBsAg level, high qHBeAg level, high APRI or FIB-4 value, low baseline ALT level, reduced HBV DNA during treatment, concomitant family history, metabolic liver disease history, and age < 40 years old are potential risk factors for developing LLV in patients with CHB during the therapeutic process.