Clinical outcomes of hepatitis B virus coinfection in a United States cohort of hepatitis C virus-infected patients

The effect of hepatitis B virus (HBV) coinfection in patients with hepatitis C virus (HCV) remains unclear. We used the National Veterans Affairs HCV Clinical Case Registry to identify patients with confirmed HCV viremia during 1997-2005. We defined HBV coinfection as a positive test for hepatitis B surface antigen, HBV DNA, or hepatitis B e antigen. We defined cirrhosis and hepatocellular carcinoma (HCC) based on the validated ICD-9 codes and determined mortality through the end of 2009. We performed Cox proportional hazard regression analyses to examine the effect of HBV coinfection stratified by HBV DNA status (positive or negative) on the risk of cirrhosis, HCC, and death adjusting for patients' age, gender, race, human immunodeficiency virus (HIV) infection, alcohol or drug use, Deyo Score, and antiviral treatment. Among 99,548 patients with HCV infection, 1,370 patients (1.4%) had HBV coinfection. Of the coinfected patients, 677 (49.4%) patients had at least one HBV DNA test done and 303 patients (44.7%) tested positive for HBV DNA. The incidence rates of cirrhosis, HCC, and death were significantly higher in patients with HBV coinfection and detectable HBV DNA compared to HCV monoinfection (36.8, 6.9, and 41.7 versus 17.4, 3.6, and 31.4 per 1,000 person-years, respectively; P<0.05 for all comparisons). After adjustment for demographic, clinical, and treatment factors, patients with detectable HBV DNA had a significantly higher risk for cirrhosis (hazard ratio [HR]=1.89 95% confidence interval [CI]=1.46-2.45), HCC (HR=2.12, 95% CI=1.26-3.60), and death (HR=1.62, 95% CI=1.33-1.99) compared to HCV monoinfected patients. There were no differences in the risk of cirrhosis, HCC, or overall mortality between coinfected patients with undetectable HBV DNA and those with HCV monoinfection (HR=1.18, 95% CI=0.90-1.55; 1.54, 95% CI=0.93-2.56; 1.08, 95% CI=0.88-1.33, respectively). Conclusion: We found that while only a small number of HCV patients were coinfected with HBV, patients with documented HBV viremia were at a significantly higher risk for cirrhosis, HCC, and overall death than HCV monoinfected patients. Absence of HBV replication was associated with a clinical course similar to that of HCV monoinfected patients. (Hepatology 2014;60:1870-1877).