Prevalence and risk factors for viral blipping in chronic hepatitis B patients treated with nucleos (t) ide analogues.

The clinical relevance of viral blipping during nucleos (t) ide analogue (NA) treatment is unclear in chronic hepatitis B (CHB). We investigated the prevalence, risk factors and clinical outcomes for those with viral blipping during NA treatment. A retrospective cohort study investigated consecutively treated CHB patients from May 2008 to February 2015 on the NAs such as entecavir (ETV), tenofovir (TDF) and lamivudine (LAM). Included patients were previously treatment naive. Viral blipping was defined as serum HBV DNA >20 IU/mL on one occasion, and not >200 IU/mL, with subsequent measurement returning to undetectable levels, that is <20 IU/mL. A total of 242 treatment-compliant CHB patients were included with 44 (18.2%) experiencing viral blipping. In multivariable Cox regression, Asian race (HR=7.40, 95% CI 1.01-54.29, P<.049), LAM therapy (vs ETV/TDF, HR=2.53, 95% CI 1.29-4.95, P<.007), higher creatinine (per SD, HR=1.47, 95% CI 1.21-1.79, P<.001), HBeAg positivity (HR=2.68, 95% CI 1.39-5.03, P<.003) and longer time to achieve undetectable HBV DNA (per month, HR=1.05, 95% CI 1.02-1.08, P=.001) were associated with an increased risk of viral blipping. Viral blipping did not show any significant association with viral breakthrough, HBsAg loss, ALT flares or disease progression. Viral blipping is a frequent event during NA therapy; however, it did not lead to any clinically significant outcomes. Thus, it may not require more frequent blood work and patient visits in clinical practice.