Ask an answerable clinical question: Hepatitis B virus (HBV) is one of the most common pathogens and infects about 4 million people worldwide. During its natural course, chronic HBV infection leads to the development of hepatocellular carcinoma (HCC). The risk of HCC increases when HBV DNA levels are more than 2000 IU/mL, and patients with low viral loads (HBV DNA < 2000 IU/mL) are usually defined as low-risk HBV carriers. However, results from a recent cohort indicated that the prognosis of low-risk patients is variable. The primary aim is to explore whether HBsAg level is associated with increased risk of HCC in low risk HBV carriers.
Acquire best evidence: We converted the clinical question to P: low-risk HBV carriers; I: hepatitis B surface antigen; C: routine; O: hepatocellular carcinoma. The numbers of articles identified were: Up To Date: 0, Cochrane Library: 11, PubMed: 156, Ovid: 98 and Index to Taiwan Periodical Literature System: 81.
Appraise the validity and usefulness of the evidence: We used the Critical Appraisal Skills Programme (CASP) to appraise these articles, and the articles of evidence level 1 are as follows: 1. Effect of serum hepatitis B surface antigen levels on predicting the clinical outcomes of chronic hepatitis B infection: a meta-analysis 2. High levels of hepatitis B surface antigen increase risk of hepatocellular carcinoma in patients with low HBV load. The results show that high HBsAg levels (>1000 IU/mL increase the risk of HCC occurrence (odds ratio 2.21, 95% CI 1.52 to 3.22; P < 0.01) compared with low HBsAg levels (< 1000 IU/mL).
Apply the result in clinical practice: The elevated HBV DNA and HBsAg levels correlate with the development of HCC. HBV DNA level played a minimal role in predicting HCC in HBV carriers of DNA levels < 2000 IU/mL, whereas HBsAg level retained its predictive power. HBsAg level < 1000 IU/mL can be an indicator of lower risk of HCC. Patients with HBV DNA < 2000 IU/mL and HBsAg level below 1000 IU/mL were associated with a 2% incidence of HCC in 20 years compared with 8% for HBsAg level > 1000 IU/mL. In clinical practice, the monitoring of serum HBsAg levels may serve as a useful biomarker.