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BACKGROUND

Prior studies have shown that precore mutations abolish and basal core promoter (BCP) mutations down-regulate hepatitis B e antigen (HBeAg) production. Thus, the presence of precore and BCP mutations in HBeAg-positive patients indicates an infection with a mixed viral population of wild-type and precore and/or BCP mutant hepatitis B virus (HBV). To date, there has been limited study of the prevalence and clinical significance of precore and BCP mutations in patients with HBeAg-positive chronic hepatitis B.

AIM

To determine the prevalence, predictors and clinical characteristics of mixed wild-type and precore/BCP HBV infection, through a cross-sectional study, in a US cohort of patients with chronic hepatitis B.

METHODS

We conducted a retrospective study of 828 chronic hepatitis B patients with HBV genotype and mutation panel testing seen at three US gastroenterology and liver clinics from June 2005 to September 2009.

RESULTS

A majority of our patients (92.3%) were either Vietnamese or Chinese American. In the HBeAg-positive cohort, 17% of patients had precore mutations only, 28% had BCP mutations only and 5% had both BCP and precore mutations. On multivariate analyses, HBV genotype C, increasing age, lower HBV DNA level and an ALT quotient >2 were independent predictors for the presence of precore and/or BCP mutations.

CONCLUSIONS

The current distinction and management recommendations for HBeAg-positive vs. HBeAg-negative patients with chronic hepatitis B should be reassessed. Additional biomarkers and treatment endpoints should be studied for their usefulness in predicting continued viral suppression after treatment discontinuation.

Medical devices are of increasing importance in cardiovascular disease and have made important contributions to patient care. These devices continue to evolve with increasing complexity. FDA regulation of medical devices involves increased stringency for higher risk and novel devices. However, there are some current opportunities to strengthen the FDA's pre-approval regulatory process and improve post-marketing surveillance. This article reviews FDA regulation of cardiovascular devices and offers suggestions for strengthening the process while focusing on examples relevant to cardiac electrophysiologists.