Prevalence of seropositive occult hepatitis B virus infection among patients received chemotherapy in Taiwan: A retrospective study.

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI), defined by the presence of HBV DNA in the absence of hepatitis B surface antigen (HBsAg), poses a risk for viral reactivation during cancer therapy. Although HBV is highly endemic in Taiwan, data regarding the prevalence and predictors of OBI among patients with cancer remain limited, which served as the motivation for conducting this study.

METHODS

This retrospective study of patients with cancer treated at Changhua Christian Hospital between January 2021 and May 2025 included patients with positive anti-HBc IgG and negative HBsAg. OBI was defined as detectable HBV DNA. Clinical characteristics were compared between the OBI and non-viremic groups by univariate and multivariate logistic regression analyses.

RESULTS

Among 1935 eligible patients, 65 (3.4 %) were diagnosed with OBI. Patients with OBI were older (67 ± 10 vs. 63 ± 11 years, p = 0.006), and a higher proportion had hematologic malignancies (24.6 % vs. 11.9 %, p = 0.002). In the multivariate analysis, age (odds ratio [OR] 1.03; 95 % confidence interval [CI] 1.01-1.06; p = 0.016) and hematologic malignancies (OR 2.47; 95 % CI 1.34-4.55; p = 0.004) were independent predictors of OBI. Among patients with available anti-HBs data, the prevalence of OBI was significantly higher in those without anti-HBs (6.9 % vs. 1.6 %, p < 0.001).

CONCLUSIONS

OBI was identified in 3.4 % of patients with cancer in Taiwan, particularly among older people, those with hematologic malignancies, and individuals negative for anti-HBs. Thus, HBV DNA screening should be considered in high-risk patients with cancer before immunosuppressive therapy.