Prevalence, correlates, and viral dynamics of hepatitis delta among injection drug users

Background: Most hepatitis delta virus (HDV) prevalence estimates from the United States are >10 years old, and HDV has shown significant temporal variation in other populations. HDV-hepatitis B virus (HBV) dual infection progresses rapidly, has more complications, and has a different treatment regimen than HBV infection alone. Accurate estimates of prevalence and risk factors are important to help clinicians decide who to screen. Methods: Injection drug users in Baltimore, Maryland, who were positive for HBV serologic markers were tested for hepatitis delta antibody (HDAb) at 2 time periods: 1988-1989 (194 participants) and 2005-2006 (258 participants). Those who were HDAb positive in 2005-2006, plus a random sample of HDAb negative, HBVpositive participants were tested for HDV RNA, HBV DNA, and HCV RNA. Characteristics associated with HDV exposure and viremia were identified. Results: HDV prevalence declined from 15% in 1988-1989 to 11% in 2005-2006. Among those with chronic HBV infection, prevalence increased from 29% (14 of 48 participants) to 50% (19 of 38 participants) (Pp.05). Visiting a "shooting gallery" (a location where people gather to inject illegal drugs) was a strong correlate of HDAb positivity (relative risk, 3.08; Pp.01). Eight (32%) of those who were HDAb positive had HDV viremia. Viremic participants had elevated liver enzyme levels and more emergency room visits. Conclusions: The temporal increase in HDV prevalence among those with chronic HBV infection is troubling; understanding this change should be a priority to prevent the burden from increasing.